How to Properly Cite Sources in APA and MLA Formats

Citation is the least glamorous part of college writing and the most consequential. Get it right and your argument stands on a foundation of evidence. Get it wrong and you lose points on formatting, frustrate your professor, and risk an academic-integrity violation—even when the mistake is honest. The good news: APA (7th edition) and MLA (9th edition) are rule-based systems you can master in an afternoon, and both are supported automatically by citation managers like Zotero.

This guide covers both systems side by side: the big-picture differences, the exact in-text rules, real examples of entry formats, and the mistakes that trip up most students.

The Big Picture: APA vs. MLA at a Glance

Feature	APA 7 (social sciences)	MLA 9 (humanities)
In-text citation	(Author, Year, p. #)	(Author Page #)
List title	References	Works Cited
Title page	Required for student papers (unless instructed otherwise)	Header with last name + page number only
Author emphasis	Year matters (recency)	Page matters (close reading)
Emphasis on	Publication date and peer review	The text itself

The memory hooks: APA is Author–Date; MLA is Author–Page. APA writers ask "when was this published?"; MLA writers ask "what page?" Pick whichever your professor assigns—do not mix them.

APA 7 In-Text Citations (Author–Date)

The basic forms

• One author, paraphrasing: (Smith, 2021)
• One author, quoting: (Smith, 2021, p. 42)—internal page required for direct quotes, preferred for paraphrases of specific passages.
• Narrative style: Smith (2021) argued that… (then, for a quote, add "p. 42" after the quote).
• Two authors: (Smith & Jones, 2021); narrative: Smith and Jones (2021).
• Three or more authors: (Smith et al., 2021). APA uses "et al." from the very first citation—unlike MLA, there's no spell-out stage.
• No author: use the title (shortened) in place of the author: ("Climate Change," 2020). If the source is a book or report, italicize the title.
• Corporate author: (American Psychological Association [APA], 2020) first time, then (APA, 2020).
• Direct quote of any length: include author, year, and page; page numbers always require the "p."/"pp." marker.
• Two works, same author and year: label them 2021a and 2021b in both the reference list and the text.

Three rules that save grades

1. Every in-text citation must have a matching entry in the References list—and vice versa. No orphans.
2. The author and year in the text must match the reference entry exactly, including spelling and "et al." usage.
3. Paraphrasing still requires citation. Changing the words does not remove the debt to the source (see our guide on avoiding plagiarism).

APA 7 Reference List Entries (Examples)

The References list is alphabetical by author's last name, double-spaced, with hanging indents (first line flush left, subsequent lines indented 0.5").

• Book: Smith, J. A. (2021). Title of book in sentence case: With subtitle. Publisher.
• Journal article with DOI (the golden format): Smith, J. A., & Jones, B. (2021). Title of article in sentence case. Journal Name, 12(3), 45–67. https://doi.org/10.xxxx/yyyyy
• Journal article without DOI: Same structure, ending with the page range only (no URL for most print journals).
• Website page: Smith, J. A. (2021, March 4). Title of the page. Site Name. https://www.example.com
• YouTube video: Channel Name. (2021, March 4). Title of the video [Video]. YouTube. https://www.youtube.com/…
• Chapter in an edited book: Smith, J. A. (2021). Title of chapter. In B. Jones (Ed.), Title of the book (pp. 45–67). Publisher.

Note the mechanics: article titles are in sentence case (only first word and proper nouns capitalized), journal/book titles are italicized in title case, DOIs are preferred over URLs, and there's no "Retrieved from" or "Accessed on" for stable sources.

MLA 9 In-Text Citations (Author–Page)

The basic forms

• One author: (Smith 42)—no comma, no "p." in MLA in-text citations.
• Narrative style: Smith argues that… (42).
• Two authors: (Smith and Jones 42). MLA spells out two authors; no comma before "and."
• Three or more authors: (Smith et al. 42). MLA switches to "et al." for 3+ (in the 8th edition it was 4+; the 9th kept the practical "3+" convention).
• Multiple works by the same author: include a short title: (Smith, Economics 42).
• No author: use the title, shortened: ("Climate" 42).
• No page numbers (web): cite the author or title alone; never invent page numbers. (MLA uses no "n.p." placeholder—you simply omit what's unavailable.)

The "one author, multiple pages" pattern

If you draw from several pages of one source, cite each point with its own page: (Smith 12), then (Smith 18). Do not stack page ranges in one citation unless the paraphrase truly spans them.

MLA 9 Works Cited Entries (Examples)

Entries are alphabetical by author's last name, double-spaced, hanging indent, with "accessed" dates used only when a source lacks a publication date or may change (e.g., wikis, live pages).

• Book: Smith, Jane. Title of Book. Publisher, 2021.
• Journal article from a database: Smith, Jane. "Title of Article." Journal Name, vol. 12, no. 3, 2021, pp. 45–67. JSTOR, doi:10.xxxx/yyyyy.
• Website page: Smith, Jane. "Title of Page." Website Name, Publisher (if different from site name), 4 Mar. 2021, www.example.com/page.
• YouTube video: Smith, Jane. "Title of Video." YouTube, uploaded by Jane Smith, 4 Mar. 2021, www.youtube.com/…
• Chapter in an edited book: Smith, Jane. "Title of Chapter." Title of Book, edited by Bob Jones, Publisher, 2021, pp. 45–67.

MLA details to memorize: the author's first name is inverted only in the first author ("Smith, Jane, and Bob Jones" for two authors), article/chapter titles go in quotation marks, container titles (journal, book, website) are italicized, months are abbreviated (Mar., Apr., Sept.), and you separate the container elements with commas, ending each entry with a period.

Six Common Citation Mistakes (And How to Avoid Them)

1. Mixing APA and MLA in one paper: decide once, per the syllabus, and enforce it in your citation manager's settings.
2. Forgetting hanging indents: in Word/Google Docs, set "Special: Hanging, 0.5"" on the paragraph format.
3. Formatting the title wrong: APA wants sentence case; MLA wants title case for works. Italicize books and journals; use quotation marks for articles and chapters.
4. Copying a citation from a database without checking: database citations frequently contain errors. Always verify against the official examples above.
5. Citing secondary sources as primary: if you read about Smith's study inside Jones's article, cite Jones (the one you actually read) and mention Smith in the text, or find the original—citing sources you've never opened is an integrity risk.
6. Trusting 100% auto-generation: citation managers are brilliant, but you are responsible for the output. Spot-check every generated entry against these examples.

How Tools Fit (and Don't)

Zotero, Mendeley, and Google Docs' citation tools will generate perfectly formatted entries if the imported metadata is correct. The professional workflow:

1. Capture sources with the browser extension (metadata arrives attached).
2. Use the word-processor plugin to insert in-text citations as you write.
3. Generate the References / Works Cited at the end—then manually verify each entry against this guide's formats.
4. Fix hanging indents and alphabetization in the final formatting pass.

The Final Word: Consistency Is the Real Standard

Professors care less that a comma is technically misplaced than that you follow one system flawlessly and credit every idea that isn't yours. Citation is scholarship's social contract: it says "these are my words, and these are the giants whose shoulders I stand on." Master it, and you stop losing points to formatting and start getting credit for rigor.

Your call to action: bookmark this guide, install a citation manager this week, and make this your ritual before every submission—check in-text citations against the reference list, verify hanging indents, and confirm you used one format consistently from the title page to the last entry.