How to cite a source in your text: APA 7, MLA 9, and Harvard

An in-text citation is the short note inside your sentence that says where an idea came from. It points to one full entry in your reference list, and the reader uses it to find that entry. When every citation matches an entry and every entry has a citation, most citation problems are already solved.

The examples below use made-up names (Nguyen, Patel, Okafor) and a made-up title so the format is easy to see. Replace them with your real authors.

When a sentence needs a citation

Cite when you:

• quote someone's exact words
• paraphrase or summarize a specific passage
• use a number, finding, or date you took from a source
• build on someone's argument, model, or definition

Facts a general reader already knows, such as the boiling point of water at sea level, usually need no citation. What counts as common knowledge depends on your field and your reader. When you cannot decide, cite.

A citation at the end of a paragraph does not cover every sentence before it. If three sentences in a row come from the same source, make that clear in the text ("Nguyen also points out...") or cite again.

APA 7: author and year

APA puts the author's last name and the year of publication in the text. A page number is required for a direct quote and encouraged for a paraphrase, especially from a long work.

• One author, in parentheses: (Nguyen, 2021)
• One author, in your sentence: Nguyen (2021) argues that...
• Direct quote: (Nguyen, 2021, p. 14), or (Nguyen, 2021, pp. 14–15) for a range
• Two authors: (Nguyen & Patel, 2021) in parentheses, Nguyen and Patel (2021) in your sentence
• Three or more authors: (Nguyen et al., 2021), starting with the first citation
• Group author: (World Health Organization [WHO], 2020) the first time, then (WHO, 2020)
• No date: (Nguyen, n.d.)
• Several sources at once: (Nguyen, 2021; Patel, 2019), in alphabetical order, separated by semicolons
• A source you only read about in another source: (Okafor, 1998, as cited in Nguyen, 2021), and only Nguyen goes in your reference list

MLA 9: author and page

MLA puts the author's last name and the page number in the text, with no comma between them and no year.

• In parentheses: (Nguyen 14)
• In your sentence: Nguyen argues that... (14).
• Two authors: (Nguyen and Patel 14)
• Three or more authors: (Nguyen et al. 14)
• Two works by the same author: add a short title, as in (Nguyen, Reading Habits 14)
• No page numbers, as on most web pages: (Nguyen)
• Words quoted inside another source: (qtd. in Patel 22)

Each citation points to an entry in your Works Cited list, and that entry starts with the same name you used in the text. When a source has no author, the entry starts with its title, and the in-text citation uses a shortened form of that title.

Harvard: author and year, with local versions

Harvard is a family of author-date styles with no single official manual. Universities publish their own versions, and they differ on commas, on whether "p." comes before page numbers, and on when to switch to "et al."

A common form looks like this:

• In parentheses: (Nguyen, 2021) or (Nguyen 2021), depending on the version
• With a page: (Nguyen, 2021, p. 14)
• In your sentence: Nguyen (2021) argues that...
• Two authors: (Nguyen and Patel, 2021)
• Several authors: some versions list up to three names and use "et al." from four, others use it from three

If your course says "Harvard" without linking a guide, ask which version it means, and follow that version even when a website shows something different.

Quote or paraphrase

Quote when the exact wording matters: a definition, a phrase you are going to analyze, a claim you are about to criticize. Otherwise, paraphrase. A paraphrase is your own sentence with your own structure. Swapping a few words in the original sentence keeps you too close to the source, even with a citation.

Either way, write the page number down while you take notes. Finding a quote again in a long PDF the night before the deadline costs time you would rather spend writing.

Mistakes worth checking for

• A citation with no matching entry in the reference list, or an entry nothing in the text cites
• A year in the text that differs from the year in the reference entry
• First names or initials inside an APA or MLA citation, where only the last name belongs
• Citing the article you read when the idea came from a source that article cites (use "as cited in" or "qtd. in," or find the original and cite that)
• A quote's page number copied from your notes and never checked against the PDF

Your school's guide decides

Style manuals leave room for choices, and departments make those choices differently. One course asks for page numbers on every citation, another names a specific Harvard version, a third has its own rule for secondary sources. Before you submit, open the guide your course links to and compare a few of your citations against its examples.

Inkwise, now in early access, suggests a next line from the PDFs you upload and shows the file, page, and exact passage behind it, so the page number is in front of you when you cite. It can also add an in-text citation to a line you accept. Check that citation against your guide like any other.