Which Citation Style Should You Use?
Your professor usually tells you. If they didn't, the answer depends on your subject area.
Here's the quick breakdown:
Style | Field | System | In-Text Format |
APA | Psychology, social sciences, business | Author-date | (Smith, 2023) |
MLA | Humanities, literature, arts | Author-page | (Smith 42) |
Chicago | History, journalism, publishing | Notes or author-date | Footnote or (Smith 2023) |
IEEE | Engineering, computer science | Numbered | [1] |
ASA | Sociology | Author-date | (Smith 2023) |
If your professor doesn't specify a style, APA is the safest default for most academic disciplines.
Still not sure? Check your course syllabus, look at the textbooks assigned for that class, or email your professor before you start writing. Switching citation styles halfway through a paper is painful.
If you're still planning your paper, a solid research paper outline will help you track which sources need citations as you go.
What Goes Into a Research Paper Citation?
Every citation, regardless of style, contains the same core information, the details that help a reader find the exact source you used.
The six core elements are:
- Author: Who wrote it (last name, first initial in APA; last name, full first name in MLA)
- Publication date: When it was published (year only in APA; full date for websites)
- Title: Name of the article, chapter, or book (titles are formatted differently by style — italics, quotes, or plain)
- Container: The journal, book, or website it appears in
- Source details: Volume, issue, page numbers (for journal articles)
- Location: DOI or URL for online sources
Miss any of these and your reader can't verify your source. Instructors notice. A reference entry missing a DOI or page range is one of the most common reasons students lose citation marks on graded papers.
The order of these elements changes by style, but the information itself doesn't. Before you can cite a source, you'll need to understand how to find sources for a research paper worth citing. Citations are especially critical when writing a research paper literature review, where every claim must be sourced.
In-Text Citations vs. Reference List: What's the Difference?
Citations are a two-part system. Most students only think about one part, and that's where errors happen.
In-text citations:
These are the short references you drop inside your paper, right after you use a source. They're brief pointers. In APA, that looks like (Smith, 2023). In MLA, it's (Smith 42). They don't interrupt the flow of reading, but they tell your reader: this idea came from somewhere specific.
Reference list entries:
These are the full source details listed at the end of your paper. Every in-text citation must have a matching entry there, with the complete author, title, publisher, date, and location information.
Here's the connection:
In-Text | Reference List Entry |
(Smith, 2023) | Smith, J. (2023). Title of article. Journal Name, 12(3), 45–58. https://doi.org/... |
(Smith 42) | Smith, John. Title of Book. Publisher, 2023. |
Think of in-text citations as signposts and your reference list as the map, you need both for the navigation to work.
The most common mistake students make? Writing an in-text citation with no matching reference entry, or building a reference list for sources they never actually cited. Both are problems, and both can be caught with a quick one-to-one check before you submit.
One more thing: the two parts of a citation don't always look the same. In APA, your in-text says (Smith, 2023, p. 42) for a quote, but your reference entry uses a hanging-indent format that spans two or three lines. They're connected, but they're not mirror images of each other.
How to Cite a Research Paper in APA Format
APA (7th edition) uses an author-date system. Every in-text citation includes the author's last name and the year of publication. Every reference entry matches that pair.
APA is the standard for psychology, social sciences, nursing, business, and education. If you're in a STEM field or writing for a science course, your instructor may also accept APA, it's the most widely taught style in US universities.
In APA, every in-text citation follows the author-date pattern: (Smith, 2023) and every reference entry matches that author-date pair.
APA In-Text Citation Format
Situation | Format | Example |
1 author | (Last, Year) | (Smith, 2023) |
2 authors | (Last & Last, Year) | (Smith & Jones, 2023) |
3+ authors | (First Last et al., Year) | (Smith et al., 2023) |
Direct quote | (Last, Year, p. X) | (Smith, 2023, p. 42) |
Group/org author | (Organization, Year) | (WHO, 2023) |
APA Reference List Format (by source type)
Journal Article:
Last, F. M. (Year). Title of article. Journal Name, Volume(Issue), pages. https://doi.org/xxxxx
Example: Smith, J. A. (2023). Climate change and coastal erosion. Environmental Science Review, 14(2), 88–102. https://doi.org/10.1234/esr.2023.14
Book:
Last, F. M. (Year). Title of book. Publisher.
Example: Jones, R. B. (2022). Foundations of modern psychology. Academic Press.
Website:
Last, F. M. (Year, Month Day). Title of webpage. Site Name. URL
Example: National Institutes of Health. (2023, March 15). Understanding anxiety disorders. NIH. https://www.nih.gov/anxiety
Formatting reminders:
Hanging indent on all entries. Double-spaced. Alphabetical by author's last name. The reference list is titled "References" (not "Bibliography").
See APA official guidelines for the full rulebook.
How to Cite a Research Paper in MLA Format
MLA (9th edition) uses an author-page system for in-text citations. The year of publication doesn't appear in the in-text citation at all, it's just the author's name and the page number where you found the information.
The reference page is called "Works Cited," not "References." That name matters, because it signals a key rule: MLA's Works Cited only includes sources you actually cited, not every source you read during research.
MLA is the standard for English, literature, film, cultural studies, and most humanities courses. If you're writing a literary analysis, a history of ideas paper, or anything in the arts, MLA is almost certainly what your professor wants.
MLA In-Text Citation Format
Situation | Format | Example |
1 author | (Last Page) | (Smith 42) |
2 authors | (Last and Last Page) | (Smith and Jones 42) |
3+ authors | (First Last et al. Page) | (Smith et al. 42) |
No page number | (Last) | (Smith) |
No author | ("Title" Page) | ("Climate Change" 5) |
MLA Works Cited Format (by source type)
Journal Article:
Last, First. "Article Title." Journal Name, vol. X, no. X, Year, pp. X–X.
Example: Smith, Jane. "Urban Heat Islands and Public Health." Environmental Studies, vol. 9, no. 2, 2023, pp. 44–59.
Formatting reminders:
Works Cited starts on a new page. Hanging indent. Double-spaced. Alphabetical by author's last name.
Running Out of Time to Format Everything?
Let our expert writers handle the research, writing, and citations for you.
Don't lose marks on formatting you could have avoided.
How to Cite a Research Paper in Chicago Style
Chicago is the only major citation system that gives you two options.
Chicago style is the only major system that gives you two options — choose notes-bibliography for humanities subjects and author-date for sciences.
Notes-Bibliography is used in history, literature, and the arts. Sources appear in footnotes or endnotes, plus a bibliography at the end.
Author-Date works more like APA and is used in the sciences and social sciences.
Chicago Notes and Bibliography Format
Footnote/Endnote:
First Last, "Article Title," Journal Name Volume, no. Issue (Year): page, DOI.
Example: ¹ Jane Smith, "Urban Heat Islands," Environmental Studies 9, no. 2 (2023): 47, https://doi.org/10.1234/es.2023.9.
Bibliography Entry:
Last, First. "Article Title." Journal Name Volume, no. Issue (Year): pages. DOI.
Example: Smith, Jane. "Urban Heat Islands." Environmental Studies 9, no. 2 (2023): 44–59. https://doi.org/10.1234/es.2023.9.
Chicago Author-Date Format
In-text: (Smith 2023, 47)
Reference List Entry:
Last, First. Year. "Article Title." Journal Name Volume (Issue): pages. DOI.
Example: Smith, Jane. 2023. "Urban Heat Islands." Environmental Studies 9 (2): 44–59. https://doi.org/10.1234/es.2023.9.
Website (Notes-Bibliography): Footnote: ² National Institutes of Health, "Understanding Anxiety," accessed March 15, 2023, https://www.nih.gov/anxiety.
Bibliography: National Institutes of Health. "Understanding Anxiety." Accessed March 15, 2023. https://www.nih.gov/anxiety.
Citing a Research Paper With Multiple Authors
Multi-author citations trip up a lot of students because each style handles them differently and the rules change depending on whether you're writing in-text or in the reference list.
The general principle: in-text citations abbreviate with "et al." to keep the prose clean, but your reference list entry always includes all the authors.
When a paper has three or more authors, most styles let you use "et al." in in-text citations to keep the prose clean but all authors appear in the full reference entry.
Style | 1 Author | 2 Authors | 3+ Authors (In-Text) |
APA | (Smith, 2023) | (Smith & Jones, 2023) | (Smith et al., 2023) |
MLA | (Smith 42) | (Smith and Jones 42) | (Smith et al. 42) |
Chicago (A-D) | (Smith 2023) | (Smith and Jones 2023) | (Smith et al. 2023) |
APA reference list notes:
APA 7th edition lists up to 20 authors. With 21 or more authors, list the first 19, add an ellipsis (...), then the last author's name.
Chicago notes-bibliography notes:
For 1–3 authors, list all names in footnotes and bibliography. For 4 or more, use the first author followed by "et al." in footnotes only. The bibliography still lists all authors up to 10.
If a paper lists an organization as the author rather than an individual, spell out the full organization name in your first in-text citation, then abbreviate in subsequent citations if a standard abbreviation exists: (World Health Organization [WHO], 2023) ? (WHO, 2023).
Common Citation Mistakes (and How to Fix Them)
The most common citation error isn't a formatting mistake, it's an in-text citation that has no matching reference list entry, or the reverse.
Here are the five mistakes that cost students the most marks:
Mistake 1: Orphaned in-text citations
- Wrong: Paper has (Smith, 2023) in text but no Smith entry in the reference list
- Fix: Before submitting, match every in-text citation to a reference entry
Mistake 2: Wrong author name format
- Wrong (APA): John Smith, 2023 / Right: Smith, J. (2023)
- Wrong (MLA): Smith, J. / Right: Smith, John
- Fix: Each style has a different format — check before building your reference list
Mistake 3: Missing DOI or URL for online sources
- Wrong: Smith, J. (2023). Climate change. Environmental Review, 14(2), 88–102.
- Right: Smith, J. (2023). Climate change. Environmental Review, 14(2), 88–102. https://doi.org/10.1234/er.2023.14
- Fix: Always include the DOI when one exists; use the stable URL if there's no DOI
Mistake 4: Mixing citation styles
- Wrong: Using APA in-text citations but MLA Works Cited format on the same paper
- Fix: Pick one style and use it throughout — if you're unsure which, check your assignment rubric
Mistake 5: Wrong edition or version of a source
- Wrong: Citing a 2005 edition when a 2021 edition exists and was assigned
- Fix: Check which edition is on your course reading list; cite that specific one
When editing a research paper, run through your citations as a dedicated pass, don't mix it with proofreading for grammar.
Citation Checklist Before You Submit
Run through this checklist before you submit. Catching citation errors here is much easier than explaining them to your professor after.
- Every in-text citation has a matching reference list entry
- Every reference list entry has a corresponding in-text citation
- All reference entries are in alphabetical order by author's last name
- Hanging indent applied to all reference list entries
- Correct citation style used consistently throughout the paper
- DOIs or URLs included for all online sources
- Author name format matches the required style
- Page numbers included where required (MLA quotes, APA direct quotes)
- Reference page title is correct: "References" (APA), "Works Cited" (MLA), "Bibliography" (Chicago N-B)
- No sources appear in reference list that weren't cited in the paper
For a broader pre-submission review beyond citations, see our complete research paper checklist.
Citations start in your introduction here's how to write a strong research paper introduction that sets up your sources properly.
Conclusion
Citations aren't just a formatting requirement, they're what separates a credible paper from one that gets flagged. Get the style right, match every in-text citation to a reference entry, and run the checklist before you submit.
If you're still unsure which style applies to your course, ask your professor before you start building your reference list. Switching styles after the fact is painful. A quick email now saves an hour later.
And if the whole thing feels like too much to manage on top of actually writing the paper, that's what we're here for. Our writers format every citation correctly, in whatever style your course requires, and every paper comes with a Turnitin report so you can submit with confidence.
Need Your Paper Cited and Submitted Fast?
Our experts handle the formatting so you don't have to sweat every comma.
- Subject-matched expert writers with 15+ years of experience
- Every style supported: APA, MLA, Chicago, Harvard, IEEE, and more
- Turnitin report included, no AI, no plagiarism
- 5,000+ students helped since 2010
Your deadline doesn't have to be a disaster.
Place Order Now
-20615.png)
-20655.png)
-9374.jpg)
-20592.png)
 (1))
-20591.png)
-20668.png)
-20612.png)
-20657.png)
-20577.png)
-20575.png)
-20578.png)
 (2))
)
 (1))
 (1))
 (1))
 (1))
 (1))
 (1))
-20419.png)
-20426.png)
-20431.png)