Yale Center for Teaching and Learning

Signaling Sources in the Body of a Paper

In academic writing, nearly every reference to a source has two parts: the indication in the body of your paper that you’re referring to a source, and the publication information a reader needs to track that source down later. The three citation styles used in this guide—MLA, APA, and Chicago style footnotes—use different methods for that initial signal that a source is being used.

Both MLA and APA are what’s known as “in-text” citation styles, which means that you give some brief information about the source directly in your sentence or paragraph, but refer readers to a section later in your paper for the full publication details. (MLA calls this later section the “Works Cited,” while APA calls it the list of “References.”) In MLA format, references to a source should mention the author’s name and the exact page you’re using directly in your paragraph. You would normally give the page number in parentheses, directly after you quote or paraphrase the source. You may give the author’s name in the parentheses, too, or include it in your sentence. Here are two very simple examples of how this might look:

In the Nicomachean Ethics, Aristotle suggests that such people “think happiness is some plain or obvious thing, like pleasure, wealth, or honour” (2).

The Nicomachean Ethics suggests that such people “think happiness is some plain or obvious thing, like pleasure, wealth, or honour” (Aristotle 2).

In either case, the reader will know to look for “Aristotle” in your Works Cited to find the rest of the information about your source.

In APA format, references to a source should mention the author’s name and give the publication year of the source. You would normally give the year in parentheses. You may give the author’s name in the parentheses, too, or include it in your sentence. (If you include the name in your sentence, give the year directly after; if you put the name and year in parentheses, put them at the end of the sentence where you quote or paraphrase the source.) Here are two very simple examples of how this might look:

Geller (2001) found that women who shop with their mothers spend twice as much on a dress as those who shop with friends.

Studies suggest that women who shop with their mothers spend twice as much on a dress as those who shop with friends (Geller, 2001).

In either case, the reader will know to look for “Geller” in your list of References to find the rest of the information about your source.

The alternative to “in-text” citations are footnotes, which give publication information at the bottom of the page. This guide describes Chicago style footnotes (and only one aspect of Chicago style—see Why Are There Different Citation Styles? and More Notes on Chicago Style Footnotes for more information). With footnotes, you are not required to mention the author, page, or year directly in your sentence. You only need to include the footnote number and to put the author and page number at the bottom of the page. But you might include one or more of these details directly in your sentence, anyway, depending on what you were trying to emphasize about the quotation. Below are some simple examples of what it might look like to introduce a source using footnote style. The references are to a band called “Rage Against the Machine,” whose music has an explicitly political message.

Rage’s adamancy in the need for an uprising is expressed by its call-to-arms, “Sleep now in the fire!”3

Rage’s adamancy in the need for an uprising is even more visible in its 1999 call-to-arms, “Sleep now in the fire!”3

One band’s adamancy in the need for an uprising is expressed by its call-to-arms, “Sleep now in the fire!”3

These examples give almost identical information, but they emphasize different elements. The first one characterizes the band as having an overall mood or message. The second one begins to imply that Rage’s ideas may have evolved over time. The third seems to treat the band as one of a collection of bands with political agendas.

In any of these cases, your reader will know to look at footnote number three for information about your source.