In-Text Citations: A Complete Guide

An in-text citation is a brief reference placed inside the body of your paper at the point where you use information from another source. Its purpose is to point the reader to the full citation in your reference list, bibliography, or works cited page. Every in-text citation must have a corresponding entry at the end of your paper, and every entry in the reference list should be cited somewhere in the text.

In-text citations come in three main formats depending on the citation style: parenthetical (author and date or page in parentheses), narrative (the author's name is part of the sentence), and numbered (a superscript number or bracketed number linked to a footnote or reference list entry). The format you use is determined by the citation style required for your assignment.

Parenthetical citations place the author's last name and the publication year inside parentheses at the end of the sentence, before the period. This is the format used by APA, Harvard, and Chicago Author-Date. When quoting directly, you also include the page number.

Sleep deprivation impairs cognitive function (Walker, 2017).

"Sleep is the single most effective thing we can do to reset our brain and body health" (Walker, 2017, p. 7).

In a narrative citation, the author's name appears in the sentence itself, and only the year goes in parentheses. This style reads more naturally when you want to emphasise the author's contribution to the discussion.

Walker (2017) demonstrated that even moderate sleep deprivation significantly reduces working memory capacity.

MLA takes a different approach. Instead of including the year in the in-text citation, MLA includes the page number because the humanities prioritise locating the exact passage being referenced. The year appears only in the Works Cited entry at the end of the paper.

Sleep deprivation impairs cognitive function (Walker 34).

Walker argues that sleep is "the single most effective thing we can do to reset our brain and body health" (7).

Note that MLA does not use a comma between the author name and the page number, and there is no "p." before the number. If the source has no page numbers (such as a web page), include only the author name: (Walker).

In engineering, computer science, and medical fields, citation styles use numbered references. Each source is assigned a number the first time it appears in the text, and that number is used every subsequent time the source is referenced. The numbers correspond to entries in a numbered reference list at the end.

Sleep deprivation impairs cognitive function [1]. Later studies confirmed this finding [2], [3].

Sleep deprivation impairs cognitive function.¹ This has been confirmed in multiple studies.²⁻⁴

IEEE uses square brackets [1], while Vancouver uses superscript numbers. In both styles, once a source has been assigned a number, that number does not change throughout the paper. If you cite source [3] again later, it remains [3].

Chicago Notes-Bibliography uses superscript numbers in the text that link to footnotes at the bottom of the page (or endnotes at the end of the paper). The first citation of a source includes the full publication details. Subsequent citations use a shortened form with just the author's last name, a short title, and the page number.

1. Matthew Walker, Why We Sleep: Unlocking the Power of Sleep and Dreams (New York: Scribner, 2017), 34.

5. Walker, Why We Sleep, 158.

Small errors in in-text citations are among the most common formatting mistakes in student papers. They may seem minor, but they can confuse readers and reduce your credibility. Here are the most frequent issues to watch for:

• Placing the citation after the period instead of before it — the citation should come before the period in APA and MLA: (Walker, 2017).
• Including the year in an MLA citation — MLA never includes the year in the in-text citation
• Forgetting the page number for direct quotes — all styles require a page number or locator for direct quotations
• Using "et al." incorrectly — APA 7 uses et al. from the first citation for 3+ authors, but MLA uses it only for 3+ authors
• Mixing citation styles within a paper — choose one style and use it consistently throughout
• Citing a source in the text that is not in the reference list — every in-text citation needs a matching reference entry