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How to cite sources in APA Style

How to cite in your text and how to write the reference for a book, a journal article or a webpage, with examples you can compare against.

In this guide

The author–date system

APA uses an author–date system with two parts that always travel together:

  • The in-text citation: the author’s surname and the year, wherever you use the idea or data.
  • The reference: the full entry in the reference list at the end of the paper.

Every work you cite in the text must appear in the reference list, and every reference must be cited at least once. The author and year must match exactly in both places.

Parenthetical and narrative citations

There are two ways to cite. A parenthetical citation puts the author and year in parentheses, usually at the end of the sentence. A narrative citation makes the author part of the sentence, with only the year in parentheses.

Book by two authors · fictitious example
Parenthetical citation
(Rivera & Okafor, 2021)
Narrative citation
Rivera and Okafor (2021)
In a sentence · fictitious example

Planning your search before you read saves time in a literature review (Rivera & Okafor, 2021).

Rivera and Okafor (2021) recommend planning your search before you start reading.

Notice the ampersand: use “&” between names inside parentheses, and spell out “and” in a narrative citation.

How many authors to name

In-text citations by number of authors (fictitious examples)
AuthorsParentheticalNarrative
One(Parker, 2020)Parker (2020)
Two(Rivera & Okafor, 2021)Rivera and Okafor (2021)
Three or more(Navarro et al., 2022)Navarro et al. (2022)
Group author(Academic Writing Center, 2023)Academic Writing Center (2023)

With three or more authors, use “et al.” from the first citation on. If two different works would shorten to the same form (same first author, same year), name as many authors as you need to tell them apart.

A group author with a well-known abbreviation can be shortened: give the full name and the abbreviation the first time, then the abbreviation alone.

Quotations: quotation marks and page numbers

When you copy someone’s exact words, add a page number (p. or pp.) to the citation. If the source has no page numbers, as with most webpages, give a paragraph number (para.) instead.

Short quotation · fictitious example

Rivera and Okafor (2021) argued that “a good research question narrows the search to what matters” (p. 34).

  • Fewer than 40 words: put the quotation in double quotation marks inside your paragraph.
  • 40 words or more: set it as a block quotation, without quotation marks, on a new line indented 0.5 in, with the citation after the final punctuation.

When you paraphrase, the author and year are enough; APA encourages adding a page number when it helps readers find the passage.

Book references

Every reference answers four questions: who (author), when (date), what (title) and where (source). For a book, the source is the publisher:

Book · fictitious example

Rivera, L., & Okafor, M. (2021). Learning to research: A guide for university students (2nd ed.). Northfield Academic Press.

  • Surname and initials for each author, with “&” before the last one.
  • The year in parentheses.
  • The title in italics and sentence case: capitalize only the first word, the first word after a colon and proper nouns.
  • The edition in parentheses after the title, if it isn’t the first.
  • The publisher, with no location. If the book has a DOI, it goes at the end.

Journal article references

Journal article with a DOI · fictitious example

Navarro, E., Quinn, D., & Moore, S. (2022). Sleep habits and academic performance in first-year students. Journal of Student Learning Studies, 14(2), 45–62. https://doi.org/10.0000/example.2022.014

  • The article title is plain text; the journal name and the volume number are italic.
  • The issue number goes in parentheses right after the volume, not italicized.
  • Page ranges use an en dash (–).
  • The DOI is a full link, with no “Retrieved from” and no period after it.

Webpage references

Webpage · fictitious example

Academic Writing Center. (2023, March 15). How to paraphrase without plagiarizing. Central Valley University. https://www.example.org/writing/paraphrase

  • A group author takes the author position.
  • If the page shows an exact date, give the year, month and day.
  • The page title is italic.
  • Include the site name unless it is the same as the author.
  • Add a retrieval date only when the content is designed to change and isn’t archived, such as a page updated daily.

If the page has no date, write “n.d.” (no date) instead of the year:

Webpage with no date · fictitious example

Parker, A. (n.d.). A quick guide to reliable sources. Campus Library Guides. https://www.example.org/guides/sources

No date · fictitious example
Parenthetical citation
(Parker, n.d.)
Narrative citation
Parker (n.d.)

Common mistakes

Common mistakes and their fixes (fictitious examples)
Instead ofWrite
(Navarro, Quinn, & Moore, 2022)(Navarro et al., 2022)
Retrieved from https://www.example.org/…https://www.example.org/…
doi:10.0000/example.2022.014https://doi.org/10.0000/example.2022.014
Northfield Academic Press, Boston, MA.Northfield Academic Press.
(Rivera and Okafor, 2021)(Rivera & Okafor, 2021)

Sources

  1. Author–date citation systemAmerican Psychological Association
  2. Parenthetical versus narrative in-text citationsAmerican Psychological Association
  3. Citing works that shorten to the same “et al.” formAmerican Psychological Association
  4. QuotationsAmerican Psychological Association
  5. Group author abbreviationsAmerican Psychological Association
  6. Elements of reference list entriesAmerican Psychological Association
  7. DOIs and URLsAmerican Psychological Association
  8. Missing reference informationAmerican Psychological Association
  9. Reference Guide for Journal Articles, Books, and Webpages (PDF)American Psychological Association

We consulted these pages on October 31, 2026.

Editorial note

This guide was prepared by APAFly with the help of artificial intelligence and checked against the sources listed above. It is for educational purposes and does not replace the American Psychological Association’s Publication Manual or your institution’s own requirements.

The examples are illustrative: the authors, works and websites are fictitious.

APAFly is an independent tool and is not affiliated with the American Psychological Association.

Spotted a mistake? Write to contacto@apafly.app

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