How Many References Should a Research Paper Have? Study of 96,685 Articles

I analyzed a random sample of 96,685 full-text research papers, uploaded to PubMed Central between the years 2016 and 2021, in order to answer the question:

How many references should you cite when writing a research article?

I used the BioC API to download the data (see the References section below).

Here’s a summary of the key findings

1- The average number of references for a research paper is 45 , with 90% of research papers having between 8 and 102 references. However, this number depends a lot on study design . For instance, a systematic review typically has 49 references while a case report has only 24.

2- As a rule of thumb, consider citing 1 reference for every 95 words (or 4 sentences) .

3- The more research you do will be reflected in the number of references you use in your paper, since high-quality articles usually have 5 more references than the median .

How many references does a typical article have?

The histogram below shows that most research papers have between 25 to 50 references, and only a few exceed 100:

Histogram showing that most articles have between 0 and 100 references and only a few have more than 100 references.

Because the distribution has a right tail, the median number of references becomes a more reliable metric than the mean. Here are a few other numbers that summarize the data:

From this table we can conclude that:

The median research paper has 39 references, and 50% of papers have between 25 and 56 references. An article can have as few as 1 reference as a minimum, and 911 references as a maximum.

Next, let’s see if the number of references depends on the study design.

Should the study design influence the number of references you use?

The table below shows that:

1- Secondary study designs (systematic reviews and meta-analyses) have the highest number of references (median = 49), which is to be expected as these articles review a large body of information.

2- Experimental, quasi-experimental and analytical designs typically have between 35 and 39 references.

3- Descriptive designs (case reports and case series) have the lowest number of references (median ≈ 25), which also makes sense as these describe the clinical story of a single (or a few) patient(s) and generally have a very short literature review section.

How often should you cite in a research paper?

Some journals may specify the maximum number of citations allowed. For instance, Nature allows articles to have at most 30 references in the main text [ Source ]. So make sure to check the authorship guidelines of the journal where you want to submit.

That being said, often is the case where we ask ourselves: am I taking too much information from outside sources? or maybe too few? So I would argue that it would be useful to know, for a given article size, how many references to cite.

If we measure the length of all the articles in our dataset combined and divide it by the total number of references, we get the following numbers:

On average, 1 reference is cited for every 95 words, that is 1 reference for every 4 sentences. In terms of paragraphs, an article has approximately 1.5 references for each paragraph.

Here’s a table that shows the median number of references cited for each word count category:

Does using more references make your article better?

Hypothesis 1: It is well-known that citing more resources is usually associated with more in-depth research, therefore, we would expect high-quality articles to include a higher number of references.

Hypothesis 2: Some experts believe that a good writing habit is to keep the number of references to a minimum (see: Essentials of Writing Biomedical Research Papers by Mimi Zeiger), so according to this hypothesis, high-quality articles should have, on average, fewer references.

Let’s find out what researchers are doing in practice and which hypothesis our data support.

In order to answer the question, I collected the journal impact factor (JIF) for 71,579 articles and divided the dataset into 2 groups:

  • research papers published in low impact journals (JIF ≤ 3): this subset consisted of 34,758 articles
  • research papers published in high impact journals (JIF > 3): this subset consisted of 36,821 articles

After controlling for study design, the group with JIF ≤ 3 had a median number of references of 37, while the group with JIF > 3 had a median of 44.

Remember that the median article overall had 39 references (as we saw above), so based on these results, we can conclude that:

High-quality articles, in general, have about 5 more references than the median article. So a comprehensive literature review and a more in-depth discussion section can make the difference between a good and an excellent research article.

  • Comeau DC, Wei CH, Islamaj Doğan R, and Lu Z. PMC text mining subset in BioC: about 3 million full text articles and growing,  Bioinformatics , btz070, 2019.

Further reading

  • How Old Should References Be? Based on 3,823,919 Examples
  • Statistical Software Popularity in 40,582 Research Papers
  • Programming Languages Popularity in 12,086 Research Papers
  • Length of a Conclusion Section: Analysis of 47,810 Examples
  • How Long Should a Research Paper Be? Data from 61,519 Examples


Appropriate Number of Sources/References for Research Paper

Using Sources in Research Paper

Writing a research paper requires gathering information, synthesizing it, critically analyzing it, and organizing it into a research paper format that is preferred or recommended by your instructor/institution. While writing certainly takes up much of the time allocated for a research paper, finding the sources to use takes the bulk of it. If you do not know how many references to use in a research paper, you can spend much of your time in an endless cycle of research.

However, when you determine the best number of sources to use and know where to find these sources, you will write a research paper within or before the deadline.

The issue of how many sources is required for a research paper is weighty. Some students we edit research papers for complain that their instructor stated that they need to add sources. Usually, we have discovered that it often occurs when the instructor does not advise on the appropriate number of references to be used. We are addressing this and other related factors in this guide.

This guide can be used as a cheat sheet for writing excellent academic term papers, assignments, homework, essay, or research paper. However, our main focus is how to integrate sources from research into your research paper, the number of references to use, where to get these sources, how to tell a good source, and other nitty-gritty.

Why must you use external sources when writing your Research Paper?

It is crucial to include outside sources in your research paper because they enrich your thinking, reinforce your arguments, and give you the power to present your arguments in the paper.

Using external sources also distinguishes your ideas from the ideas of others ? you get the chance to appreciate the work of other researchers, which by extension, helps prevent plagiarism.

When writing an assignment, you draw ideas, examples, or evidence from the sources to support and reinforce your ideas and stance. It is for this reason that these sources are cited. However, when writing a research paper, it is a thesis-driven paper rather than a source-driven paper ? like the annotated bibliography. Therefore, ensure that the sources you are using are related to your thesis or central argument.

You use evidence from the sources to support your thesis statement. In this sense, the scholarly sources help you contribute to the scholarly conversation with experienced scholars on your topic. You, by extension, give authority, relevance, and strength to your research paper, essay, or dissertation when you use credible sources.

Given the significance of external sources, not only when writing a research paper but also when writing a dissertation, essays, theses, reports, and term papers, it is important to use credible scholarly sources. Using credible sources helps your audience to see how you have backed your assertion with evidence. Ensure that your research paper has various sources to have a rounded view, diverse perspective, several voices, and reduce the chances of bias.

What is the best number of sources for a research paper?

As a general rule, the minimum number of sources to use in a research paper should match the number of pages of your research paper. That is to say that every page of a research paper must have one reference (not citations). So, assuming you are writing a 7-page research paper, you would need at least seven sources, although five can suffice. Of course, the number of sources is further determined by factors such as institutional requirements, rubrics, instructions from your instructor, and the complexity of your paper. However, maintaining such a match ensures that your content has well-balanced citations, critical analysis, good organization, and flow of ideas. 

If you are unsure about the number of sources to use in your research paper, the best thing to do is to ask your instructor soon as you are assigned to write a research paper.

Otherwise, if no response is forthcoming, let the minimum number of sources be the same number as the number of pages for you to align the length of the research paper to the quality of its content.

When using sources, don?t just throw them in your text as in-text citations; use them sparingly. For example, you can use them when giving examples, presenting arguments, quoting, paraphrasing, or summarizing ideas from the sources.

And, of course, your entire paper should not be about the sources. Instead, analyze, criticize and write facts, then borrow from these sources to bolster your arguments. That way, you can write a top-grade research paper that scores you better marks. Check out our research paper writing guide for more insights.

Key Determinants of the Number of References/Sources to use

Many factors influence the number of references you can use in a research paper or essay. They define the right number of references, which means doing it right to avoid plagiarism. We advise that you determine the number of sources when writing a research paper outline so that the scope of your paper and research is defined early enough. You have a limited number of pages to write an essay. You cannot use every source available on your topic. You have to be very picky and meticulous.  Here are some factors to consider when the number of references to use is not apparent.

Your personal Choice

If you notice that the instructor has not given you the exact number of sources to use or has allowed you the freedom to use whatever number of sources that you please, you need to be very careful when making such a choice.

We recommend using a manageable number of sources. You could go with as many as you want but don?t overdo it. Ensure that each source from where you summarize, paraphrase, or quote ideas is appropriately cited in the research paper. If you do not cite the sources, you might be accused of plagiarism that has severe consequences.

If you are unsure about the sources to use, we can help you. Our research paper writers understand how to plan, write, and format research papers with optimum references.

How challenging the topic is

In-depth and challenging topics require slightly more sources for a standard research paper. However, even when it is a short or long research paper, the complexity of the topic will ultimately determine the number of sources you use.

When writing about a complex topic that requires arguments, especially for controversial issues, it is best to use many sources to support, refute, or weigh arguments. In this case, researching further will help you identify good sources and facts that you can use to refine your arguments and support the research paper claims. On the other hand, simple topics that are direct will not need many references.

In short, the more complex the topic, the more the sources.

Content of the research paper

The subject matter of your research paper will define the number of references in your reference list. If, for instance, you are writing about a less studied topic or field, take the example of neuroscience or nanotechnology, you will notice that there is a dearth of previously written papers that you can cite. Newer fields of study also have few published studies. In this case, focus on the relevant current sources and not the number.

Paper Instructions/Rubric

Some teachers are generous enough to include the minimum sources to use in your research paper assignment. However, when the number of sources is specified, you better stick to it because failing to do so might lead to a deduction of marks.

A teacher who specifies the sources to be used understands the confusion that often comes when none is specified. They also do so to ensure that students engage in research to find credible sources.

Another reason is that specifying the resources also limits the scope of research one needs to take to write a paper. It makes the research process enjoyable so that everyone is comfortable, including the sources. It is also a move to check whether the students have grasped the formatting styles and using sources. For instance, the APA formatting style follows a different convention from Chicago and MLA. 

Data and Statistics

In most research papers, such as nursing research papers, philosophy research papers, and others, you will most likely apply statistics and data. If your research paper requires data and statistics from various sources, you will use many sources. For example, you need to provide quantifiable evidence when writing a quantitative research paper. Otherwise, for a paper that dwells on qualitative research, you will not need so many sources.

Suppose, for instance, you state that 85% of college students in America hate writing research papers due to the tedious writing and research process. In that case, you have to give facts from higher education journals, newspaper articles, periodicals, or relevant educational organization websites.

Because you are not the one that conducted the research, you have to acknowledge the source.

Institutional Research paper Standards

Most institutions have their norms. Colleges, universities, and high schools or professional bodies have their preferred ways of doing things. The same applies to research papers. For instance, most nursing schools require students to use nursing peer-reviewed journals published in the last 5 or 7 years.

Some schools will stick to a given number of references for research papers. For example, some schools require undergraduates to use at least ten sources in their research papers, but some might need less or more depending on the course. Others will simply tell you to match the sources to the pages of your content. So, if you are writing an 8-page research paper, for instance, you will need to use at least eight sources.

How to use sources in your Research Paper or academic paper

There are three major ways of integrating external sources into your research paper to support your central argument or present a counterclaim:

  • Summary -You can summarize the many ideas that a given author or source has discussed using your own words and citing the author (s) of the specific source.
  • Paraphrasing ? you can also paraphrase by stating the ideas from the other source using your own words akin to summarizing. You need an appropriate citation even though you are using your own words if the ideas, evidence, or facts were drawn from another source.
  • Quotation ? when you lift the exact words from another source, you will be quoting. There are rules for a quotation as per the different formatting styles such as MLA, APA, Chicago, or Turabian formats. You must give the exact page number of the source where you are drawing the quote.

Paraphrasing entails writing in your own words. Do not fall into the temptation of changing a few words from the original source or simply restating the information exactly as is using different words. That will be considered Plagiarism. If you cannot state the words using your words, you are better off using a direct quotation.

When using evidence from other sources in your paper:

  • Mention the author, date, and any relevant information when paraphrasing, summarizing or introducing a quote. For example, you could say, According to Oliver (2015) ? or Oliver (2016), opines that?
  • Include a complete bibliography of the source material
  • Relate your source and analysis to your original thesis

What sources should you use for a research paper?

You are probably wondering where to get the sources or references for your research paper. Although most of the instructors will partially cover this, it is an important aspect not only for research papers but also for your entire high school, college, university, or graduate-level papers.

There are three main categories of academic resources for research papers: primary, secondary, and tertiary research paper sources. The primary sources are based on different studies such as surveys, poems, court records, diaries, journals, interviews, research papers, and fieldwork, primarily published in academic journals.

The secondary resources have an analysis or description of the primary source. These could be articles, peer-reviewed journals, and books that interpret or review other sources, encyclopedias, dictionaries, and textbooks.

The tertiary sources organize and help in detecting secondary and primary material. They include indexes, databases, or abstracts.

To get a good source, you need to come up with keywords relating to your topic. Once you have these seed keywords, the first step is to search online. You can use search engines such as Duckduckgo, Google, Bing, or Yahoo. You will get a lot of information that can further help you build up your list of keywords for further search.

If you are to select good sources, only choose credible sources. For example, avoid blogs when writing a paper, same as Wikipedia. However, Wikipedia and blogs can be a great starting point to understand your topic.

You can get books, articles, and journals from online scholarly databases such as Ebscohost, Google Scholar, ProQuest, LexisNexis, PubMed, OVID, etc. the scholarly articles from these databases are reliable and relevant as long as you match them up to your topic.

You can also check magazines and newspapers. They are a great source of current news, latest occurrences, shifting debates, etc. You can check out credible news outlets such as The New York Times, Times Magazine, Forbes, Wall Street Journal, and many other platforms.

If you prefer it the old way, you can visit the library and get good sources for your research paper. Librarians are usually very resourceful and can help you locate both online and offline resources as long as you specify your topic to them.

List of Credible Research Paper Sources

If you are writing a paper, you should focus first on getting a good topic then using it to develop keywords that you can use to search for reliable sources for your assignment. The process can be challenging, especially given that the internet has too much information. Good sources strengthen your arguments. Avoid websites and Wikipedia, but use them to learn more about your topic.

Here is a list of sources to get your facts from:

Research Organizations

  • Rand Corporation
  • The Center for Economic Policy and Research
  • The Milken Institute
  • Institute of Defense Analyses
  • National Institute for Health Research
  • The National Institute for Health and Care Excellence
  • The National Health Service

Academic Libraries and Databases

  • Sage Publications
  • Science Direct
  • Springer Science + Business Media
  • Google Scholar

Professional Standards Organizations

  • International Organization for Standardization
  • American Psychological Association
  • American Medical Association
  • National Institutes of Health (NIH)
  • International Atomic Energy Agency
  • National Association of Professional Engineers

How to Tell the Credibility of Sources

There are many preferred methods used to determine the credibility of references to be used not only in research papers but also in other types of academic writing tasks. However, the CRAAP test is the widely used test that helps determine the fitness of a reference to be used in a research paper. You can use the test to evaluate the quality, relevance, and trustworthiness of a source based on its Currency, Relevance, Authority, Accuracy, and Purpose.

Currency: the timeliness of the information

  • When was the information published or posted?
  • Has the information been revised or updated?
  • Is the information current or out-of-date for your topic?
  • Are the links functional?
  • Are the arguments relevant to current affairs?
  • Does the source adequately cover the topic you are researching?

Relevance: the importance of the information for your needs

  • Does the information relate to your topic or answer your question?
  • Who is the intended audience?
  • Is the information at an appropriate level (i.e., not too elementary or advanced for your needs)?
  • Have you looked at a variety of sources before determining this is one you will use?
  • Would you be comfortable using this source for a research paper?

Authority: the source of the information

  • Who is the author/publisher/source/sponsor?
  • Are the author's credentials or organizational affiliations given?
  • What are the author's credentials or organizational affiliations given?
  • What are the author's qualifications to write on the topic?
  • Is there contact information, such as a publisher or e-mail address?
  • Does the URL reveal anything about the author or source? examples: .com (commercial), .edu (educational), .gov (U.S. government), .org (nonprofit organization), or .net (network)

Accuracy: The reliability, truthfulness, and correctness of the content

  • Where does the information come from?
  • Does evidence support the information?
  • Has the information been reviewed or refereed?
  • Can you verify any of the information in another source or from personal knowledge?
  • Does the language or tone seem biased and free of emotion?
  • Are there spelling, grammar, or other typographical errors?

Purpose: the reason the information exists

  • Is the source objective enough?
  • What is the purpose of the information? To inform? Teach? Sell? Entertain? Persuade?
  • Do the authors/sponsors make their intentions or purpose clear?
  • Is the information fact? Opinion? Propaganda?
  • Does the point of view appear objective and impartial?
  • Are there political, ideological, cultural, religious, institutional, or personal biases?

Dos and Don?ts when using References

Our team of research writers has been generous enough to share some wisdom on what you should do or not do when using references in your academic writing.

  • Avoid repeating references in your reference list.
  • Balance your discussion with citations of external literature by experts, scholars, and authors.
  • Avoid repeatedly citing yourself in your papers.
  • Be extremely careful when citing old sources because it is most likely they have obsolete arguments.
  • As a rule of thumb, only go back at most five or six years back. Beyond that, a source gets obsolete. However, if seminal works prompt an idea you are researching, you can use those old sources. The same applies to historical sources.
  • Confirm the credibility of a source before using it in your paper.
  • Never fake sources when writing an academic paper; it is plagiarism.
  • Everything cited within the text must feature in the reference list
  • Be keen when creating the references page. Title it as per the required formatting style: References ? APA; Reference List/Bibliography ? Harvard, Bibliography -Chicago, Oxford, Turabian, etc.
  • Some parts such as the discussion, literature review, and background might have more references than other parts.
  • Never include a citation in the conclusion.
  • You can sparingly use a citation in your introduction. Do not overdo it.

Related reading: How to find textbooks online for free.

FAQs about the Number of Sources for a Research Paper

How do i determine the number of sources to use in my research paper.

  • Check the assignment instructions/rubric/guide
  • Ask your instructor or professor
  • Peg it on the length of the paper
  • Personally assess to determine what number is appropriate

What sources do I use in my research paper?

Some of the best sources or references to use in a research paper include magazine articles from trusted media houses, scholarly articles, peer-reviewed articles, reputable and reliable websites, journal articles, periodicals, governmental publications, organizational publications, PowerPoint presentations from class, dissertations, and other sources suggested in your rubric, instructions, or research paper prompt.

How many sources should I use in a 20-page paper?

It depends on the scope of the paper, its technicality, and the content required. If the 20-page paper is simple, assuming it is like a normal essay, you will need to use 20 sources. However, if the 20-page paper in question is complicated, such as papers in medicine, geography, history, anthropology, aviation, or nursing, you can extend the sources to 40. If there is too much statistics and data, you could go as high as 45-50, but you have to ask your instructor the optimum number of sources to use.

How many sources can I use in a 15-page essay?

If you are writing a 15-page paper, you should prepare at least 15 sources to use in the paper. However, you are allowed to extend to 20 sources if the topic is demanding or you want to draw meaningful conclusions using insights from multiple sources.

How many sources for a 10-page paper?

As a standard rule of thumb for research paper sources, a page should have one source. Therefore, a 10-page paper should have a minimum of 10 references or credible sources. However, if the topic is too complex, you can still use the ten or 15 sources. Thus, ten sources are efficient for a college, university, or graduate-level 10-page research paper.

How many sources for a 7-page paper?

For a standard 7-page paper, you should use a minimum of 5-7 sources. Using the minimum allows you to objectively present the ideas and tie them to the topic you are writing about. Even though you can use 10-15 sources, check on the limit as you want to make sense of the paper, based on arguments rather than mere reports of who said what.

How many sources for a 5-page paper?

Assuming that a page requires at least one source, a five-page paper can have a minimum of 5 sources/references. However, you might use more sources in a 5-page paper but be mindful not to dilute the content so that it becomes overly descriptive than critical. We would suggest not exceeding eight references for a standard 5-page paper. However, you can use ten references but be very vigilant.

how many in text citations should a research paper have

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Optimum number of references for a research paper – and how to achieve that number

There is no universal standard or rule for the number of references that should appear in a research paper. The number of references depends on several factors , chiefly the study discipline and specific topic, the article type and the target journal’s preferences.

Reference number by study discipline and niche

  • Discipline : The average number of references per article has been observed to be higher for social sciences, physics and ecology than for medical sciences.
  • Niche : If you are working on a highly researched topic, you might end up having a lot of references. However, within a broad field, a niche or narrow subdiscipline or a very new and original idea, say ‘indigenous languages of the Mascarene Islands’, might have very few pre-existing studies, so you may not have very many studies to cite. 

Reference number by article type

  • Reviews : Review articles , systematic reviews and meta-analyses tend to have long reference lists because, by definition, such studies critically assess the data from existing studies.
  • Reports : Case reports or other types of short reports cite very few references because the primary focus is the authors’ current findings.
  • Original : An original article would have a reference number between that of review articles and short reports.

Reference number by journal 

Some journals might have restrictions on the maximum number of references, further contingent on article type and total word count. For example, references might be capped at three (e.g. for a ‘Disease Note’ article in the Journal of Plant Pathology ) or could be as high as 100 (e.g. for reviews in PLOS Pathogens ). In Nature , original articles typically have 30–50 references.

Our recommendation : Always consult the journal’s author guidelines for specific limits, if any. Where not specified, skim recently published articles in that journal for a rough estimate.

Tips to help you optimise your reference list

Not every paper you might have read during the literature review needs to be included. To strike the right balance between too many or too few, keep the following key points in mind when compiling your references .

1. Scan academic journals in your field 

Study the trends of journals in your discipline, with a focus on the article type you have in mind. Get a rough idea of the number of references typically listed by checking how many references other authors have included in their papers. 

2. Strike a balance between retaining and removing

Are some of your statements supported by a long list of references? Try to sift through the noise and retain only those that strongly support the statement and are not repetitive. For example , among several studies that have used the same genetic analysis approach in different species, choose the one most relevant to your study.

‘ Responsible citation ’ requires that you consult and understand the content of a paper before choosing to cite it, rather than including it just because others have cited it. In short…

  • Retain references if they are truly relevant to your research.
  • Remove references if you have not read the cited article fully.

There is no standard number of references for an article. However, the following pointers should help you work towards an optimal number.

  • Keep track of general trends for specific article types by examining the most recent relevant publications.
  • When a limit is prescribed, treat it as sacrosanct; do not exceed it.
  • When no limit is indicated, cite an adequate number required for your paper.

With practice, you will learn to strike the perfect balance of not too many and not too few!

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APA In-Text Citations for Research Writing

how many in text citations should a research paper have

Why Use In-Text Citations?

When writing a journal article, literature review, convention paper, or any other academic document, authors must include in-text citations whenever they refer to, summarize, paraphrase, or quote from another source. In addition, every time a work is cited within a paper (in APA style, a parenthetical citation), a corresponding entry must be included in the reference list.

How to Cite a Research Paper Using In-Text Citations

The rationale behind citing other people’s publications in your own manuscript is that you want to avoid intellectual dishonesty by giving credit to whoever reported a finding first or invented a specific technique. This is not only an ethical question, as being “sloppy” with your sources can easily be considered plagiarism (and even self-plagiarism , if you fail to refer to your own work), which can have legal consequences and damage your reputation.

General rules for what information should be provided when citing sources in a research paper vary across fields and depend on the type of source (e.g., books, journal articles, patents, conference proceedings, websites, etc.). We are not going into such differences here but will focus on the correct way of referencing other people’s research in your own paper according to one of the most common styles used to cite sources within the social sciences and in several other academic disciplines , that is, APA (American Psychological Association) style .

In research papers, in-text citations are most commonly used in the Introduction and Discussion Results sections. The following guidelines and examples are taken from the APA Publication Manual, 6th edition, 2nd printing , which details rules and application of APA style in research papers, including in-text citations, endnotes/footnotes, and references. For more information, consult the APA Style Manual website .

This resource provides detailed guidelines for citing sources in your paper and includes examples of in-text citations for reference by research authors. Before submitting your manuscript to a journal or publisher, be sure to use our free APA citation generator for your references and in-text citations.

APA Citation Rules: The Basics

Order and structure of in-text citation content.

When using APA format, follow the “author-date” method of in-text citation. Write the author’s last name and publication year for the source in parentheses and separate these pieces of information with a comma.

When referring to external work or referencing an entire work but not directly quoting the material, you only need to make a reference to the author and year of publication and not the page number in your citation.

The results of the first enzyme study (Chen et al., 2014) revealed several relationships.

If you mention the name of the author of the work in the sentence or earlier in the paragraph, you only need to include the year of publication in the citation.

Chen (2014) discusses several relationships revealed in this study.

Verb tense used in referring to other works

APA style requires authors to use past tense or present perfect tense (NOT present tense) when using signal phrases to refer to or discuss previous research (have a look at this article for more details on the correct tenses for different parts of a research paper ).

Radnitz (1995) found… / Radnitz (1995) has found…

Placement of in-text citations in the sentence (no quotation)

When referring to a specific work or works, place the citation (publication date only) directly after the author of the study referenced.

Klinge and Rogers (2010) found that mirroring is instrumental in developments of performative gender roles.

When giving information that reflects the results or implications of previous work, place the citation (author and publication date) at the end of the sentence.

Mirroring has been found to be instrumental in the development of performative gender roles (Klinge and Rogers, 2010).


Always capitalize author names and initials in in-text citations.

(r. kazinsky, 2014)    (R. Kazinsky, 2014)

In-Text Citation Rules for Short Quotations

When quoting directly from a work, include the author, publication year, and page number of the reference (preceded by “p.”).

Method 1 : Introduce the quotation with a signal phrase that includes the author’s last name; the publication year will follow in parentheses. Include the page number in parentheses at the end of the quoted text. Note that the quotation marks surround the text only, and not the parenthetical citation.

According to Khan (1976), “Graduate students tend to apply more diverse methods during their first two years of research” (p. 45). Khan (1976) noted that “graduate students tend to apply more diverse methods during their first two years of research” (p. 45), a fact that has profound implications for research departments.

Method 2 : If the author is absent in the signal phrase, include the author’s last name, the publication year, and the page number together in parentheses after the quoted text.

Researchers noted that “graduate students tend to apply more diverse methods during their first two years of research” (Khan, 1976, p. 45), but they did not offer a suggestion as to the cause.

In-text Citation Rules for Long Quotations

Long direct quotations are those with at least 40 words of quoted text in a row. Long quotes should be placed in a separate block of lines without quotation marks, similar to creating a new paragraph. Begin the quotation on a new line and indent 0.5in/1.27cm from the left margin. Type the entire quotation within these new margins using double-spacing. Include the parenthetical citation after the final punctuation mark.

Khan’s (1976) study found the following: Graduate students tend to apply more diverse methods during their first two years of research, especially when conducting research in teams of three or fewer with no senior researchers    present. This tendency could be attributed to either a misunderstanding of correct methodology or to a feeling of freedom to explore different approaches that the researchers have yet to employ. (p. 45)

Summarizing and Paraphrasing Other Works

When  paraphrasing another work , you only need to cite the author and year of publication in your in-text citation. It may be a good idea to include the page number as well if the paraphrased information is located on a specific page of the original text. APA guidelines encourage this inclusion but do not require it.

According to Khan (1976), new researchers tend to use more diverse methodologies. New researchers tend to use more diverse methodologies (Khan, 1976, p. 45).

Common Signal Phrases for Introducing External Works

  • According to Johnson (publication year)…
  • As Johnson (publication year) has noted…
  • Johnson and Smith (publication year) contend that…
  • As Johnson’s (2011) study revealed…

Citing Works by Multiple Authors/Editors

When making an in-text citation of works by multiple authors, there are specific rules to follow depending on the number of authors of a publication and the number of times you cite the same works.

Citing Multiple Works in One In-text Citation

When citing more than one source in the same in-text citation, list all sources in the standard way and separate them with a semi-colon. List the sources alphabetically (by author’s last name or by title if no author is given) in the order they appear in the reference list.

(Marsh, 1997; Johnson, 2002). (Kazinsky, 2017; “Three Different Roads,”  2013).

Citing Works by the Same Author with the Same Publication Year

When citing two or more sources with the same author and year of publication, assign lowercase letters directly after the year of publication (a, b, c) according to the alphabetical order of titles. You will use the same alphabetical designations in your in-text citations that you do in your reference list.

The incidence of West Nile virus in Florida increased between 2002 and 2004 (Dickens, 2014a). According to Dickens (2014b), “these viral infections were precipitated by record levels of rainfall around the peninsula” (p. 150).

Citing a Work Quoted in another Source

Work quoted or paraphrased in another text is called a “secondary source.” While in your reference list you must cite the primary source as well, in your in-text citation you will add the words “as cited in” followed by the secondary source. For example, if a review article by Franklin you are citing includes a useful quote by Adams that supports your paper, your in-text citation would look like this:

According to a study by Adams (as cited in Franklin, 2016), 25% of all US federal prisoners have been diagnosed with some form of social disorder. Adams (as cited in Franklin) contends that this statistic “reflects the dehumanizing conditions of most federal institutions” (p. 76).

Citing Web Pages

Entire website.

When citing an entire website (with no specific webpage or article given), simply provide the title and web address within the text of your paper. No citation is needed in the References.

The American Psychological Association includes detailed information on how to apply APA citation (

Webpage with author(s)

A webpage with an individual author or authors should be cited in the same way as other texts, with the name or names written first, followed by the publication year.

There were 523 new cases reported in 2011 alone (Kristoff, 2012).

Webpage with a group author

Treat group authors as individual authors in in-text citations, but instead of the author’s last name, include the name of the group.

Claustrophobia afflicts one in five Britons (The Surrey Group, 2003).

Webpage with missing information

Even when some central information is missing from a website (e.g., no author, date, or webpage title), you may still cite it as a source if you use the correct formatting. For information on how to cite a website with missing information, visit the APA Style Blog post on  Missing Pieces .

Citing social media sources

For a more comprehensive explanation of social media citation guidelines, visit the APA Style Blog post on  How to Cite Social Media in APA Style .

And when submitting your finished AP document to journals or for a class assignment, be sure to get professional English editing services , including academic editing , manuscript editing , and research paper editing services . Professional editors with experience in APA, AMA, MLA, and other popular style guides will make sure that your document’s citations and references conform to the journal of your choice.

Wordvice Resources

Wordvice provides a variety of other articles on topics such as the number of references your manuscript should contain , different citation styles if your target style does not use APA, and how to paraphrase correctly when citing sources in your paper, as well as more general advice on how to write research papers on the Wordvice academic resources website .

how many in text citations should a research paper have

Citing Sources: In-Text Citations

In-Text Citations

  • Chicago / Turabian Style
  • ACS Citations
  • Online Resources

What is an In-Text Citation?

An in-text citation is a reference made within the body of text that alerts the reader to a source that has informed your own writing. These are also called parenthetical citations . 

In-text citations provide breadcrumbs to your readers, allowing them to trace the origins and path of your arguments through the sources and authors you read and built upon. 

To Quote or Not to Quote?

This is a question that you may have asked yourself while writing a paper. Should you quote this source (in a direct quote) or should you add in this information into your paper in a different way? To answer that, we must look at the different ways to add information from sources into your paper. 

Direct Quotes

Quoted material should be reproduced word-for-word from the source text. This quote should be housed within quotation marks, and the author's last name, year of publication, and page number should be included to direct the reader to the original source. Direct quotes should be used only when you cannot express the thought or ideas presented in a better way or when a direct passage of the original source is needed to make your argument. 

Paraphrases and Summaries 

Paraphrasing is when you, as the researcher and author, put a passage or idea from another's work into your own words. A paraphrased passage is usually shorted and more condensed than the original source. Summarizing is very similar to paraphrasing, but instead of using only a passage or idea, a summary condenses an entire source, or source section, highlighting the main points and/or ideas. Paraphrases and summaries should be the most common type of citations used within the text of your paper. 

Adding In-Text Citations

Whenever you use an outside source to build your argument, you need to add in the creator's information to give credit to the original source. Whether you use a direct quote or a paraphrase, you should keep the following tips in mind.

  • It is very easy to throw in a quote or paraphrase here or there, but without context, your reader will not be able to follow the path of your thinking and reasoning. To avoid this, tread each citation like its own mini essay. Provide an introduction (in your own thoughts and words) to the citation, providing a reason as to why this is important to both your paper and your reader. Next, place the quote or paraphrase. Finally, tie the citation back in with your larger argument. 
  • It is tempting to pull a direct quote from a random source to fill your quota a required citations or to fill in a hole where a source is needed. This should be avoided because it weakens your overall paper and argument. Use sources that build upon your arguments (or provide counterpoints). Don't pull only a direct quote or two from a paper and use nothing else. Your work should be a part of the lager conversation, and the sources you use should help you build your argument and help place you within the conversation. 
  • A direct quote should only be used when there is no way that you could articulate a point or an argument better. Paraphrasing and summarizing is better because you are building off of the overall ideas and themes of a paper rather than resting your arguments and evidence on only a direct quote.
  • A source should never be used only once within your paper, nor should they be used so frequently that it seems you have only one source. A good rule of thumb is to include 1 source for every page assigned (so a 5 page paper will use roughly 5 sources), and each paragraph will usually have about 2 citations within it. This means that each source you use should appear within your paper a few times (and most of the citations should be for paraphrases and summaries of arguments). 

Rules of Thumb

Below are some general rules to keep in mind when writing a paper. If you have questions about a specific assignment and its requirements, contact your professor.

  • A general rule of thumb is that you will need 1 source for every page. This does not mean that you will use only one source on each page, but instead, if you have a 5-7 page paper to write, you will need 5-7 sources that will be inter-dispersed throughout your paper. 
  • Your professor will most likely inform you of how many sources you will need in your paper
  • A good rule to follow, is to have about two sources per paragraph. This means that each source will be cited more than once throughout your paper. 
  • Your paper should have more paraphrased and summarized citations than direct quotes. To ensure that you are using direct quotes effectively, use a direct quote only when the original source states the point better than you would be able to, or when you are directly referencing the original source. 

In-Text Citation Cheat Sheet

When you  do not mention the author's name in your sentence , the author's name, date, and page number are placed in parentheses at the end of your sentence. 

When you  mention the author's name in your sentence , the date and page number is placed in parentheses at the end of the sentence.

When you cite  more than one work by the same author , ensure that you add in the titles of the work to differentiate between the works. 

When the work has  no author , in lieu of an author's name, begin with the first few words of the citation as it will appear alphabetized in your Work Cited or Reference page at the end of the paper.

When you  quote or paraphrase a quotation from a book or article that appeared somewhere else , make note of the secondhand quotation, or find the original source and cite that. 

When you are  citing several sources for a single passage , include all citations with a semi-colon (;) between each source.

When you  paraphrase a whole passage or several passages , begin your citation with the author's or article's name and end it with the publication date and page number. 

Common Signal Phrases

Below are some common signal phrases to introduce a quote, paraphrase, or summary as an in-text citation. 

Says:  the verb introduces the quotation as information

Argues in favor:  the verb indicates that the source is providing evidence or reasons for a position

  • Demonstrates
  • Holds 
  • Illustrates

States erroneously:  the source makes a statement that you are skeptical about (be careful of your tone if you use these)

  • Claims 

Continues:  you continue to refer to or quote the source

  • Continues 
  • Goes on to say
  • States further

Agrees:  the verb indicates that the source agrees with another source or with the position you are advancing

Yields: the source agrees that a conflicting point is valid 

  • Acknowledges
  • Recognizes  

Argues against:  the verb indicates that the sources is responding critically to another source or with the position you are advancing

  • Contradicts
  • Refutes  

Implies:  the source presents information either tentatively or indirectly 

  • Proposes 
  • Suggests 

Concludes:  the source draws a conclusion from previous discussion 

  • Concludes 
  • Decides 
  • Determines 
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  • February 21, 2022

What is referencing?

Referencing can be termed as the act of acknowledging or recognizing the sources you derived your ideas from when writing any academic work.

Many people involve themselves in this act intentionally and unintentionally. Plagiarism is taking one’s writing or ideas and claiming them as yours without proper acknowledgement. Poor organization and time management can be a major factor in this act. To avoid being an ‘academic theft’, one needs to decline from the habit of stealing people’s ideas (plagiarism) without giving them the credit they deserve, so this is where referencing comes in.

Why is referencing important?

When it comes to research writing be it a journal, article, review papers, projects, thesis etc referencing is an important factor one should never neglect. References help us acknowledge the contributions of other writers and researchers in our field of study.

Regarding the right number of references, just as there are two sides to a coin, there are good and bad reasons why one should use as many as possible references. Let’s take a quick look at the disadvantages.

Flaws of having too many references

  • A major disadvantage of having too many references is that it may hinder the flow of the paper. Secondly, it may show that you are not very well versed in your field of research and have to rely on an overwhelming number of citations.
  • It sends a signal that your work is not very interesting.
  • It puts your work at risk, making other reviewers overly critical of your work.
  • You tend to flood your work with too many ideas.

Yes, referencing is a way of giving credit to writers from whom you have borrowed words and ideas. However, endeavor not to give too much credit so your hard work wouldn’t have to suffer for it.

Benefits of too many references

The good side to having many references is stated below, It:

  • Enables your readers/reviewers to consult the original articles or sources.
  • Helps identify the salient points when you quote the original.
  • Shows readers the scope and depth of your reading.
  • Incorporates information by evaluating, comparing and contrasting it to show understanding.
  • Relates to other research that leads up to your study.
  • Helps you take a side to a scholarly argument objectively.

How many references is enough?

Having compared both sides of the coin, we conclude that the number of references that should be used in a research paper depends on the relevant literature available in a particular field of research. So, do not go with less and too much either. Let there be a balance in your choice. Just cite about enough sources that are necessary for your paper.

There are no specific ranges that are seen as standard. The number of references also depends on the kind of research you’re undertaking, it may be a journal, an article, a thesis or a review paper.

Overall, do not let your scholarly contribution be drowned in the sea of references.

Do you need help with your referencing? Speak with a consultant.

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