• 4-minute read
• 19th March 2019

A Guide to Chicago Author–Date Citations

The Chicago Manual of Style sets out two approaches to referencing sources in academic writing, one of which uses parenthetical citations. And while the basic citation format is easy to grasp, the rules vary in some situations. In this post, then, we’ll look at how to ensure your referencing is always error free when using Chicago author–date citations.

1. Basic Chicago Author–Date Citations

The Chicago author–date system requires you to cite the surname of the author and a year of publication in round brackets. This usually goes at the end of the relevant clause:

There are many approaches to referencing (Fry 2001).

If the author is already named in the text, do not repeat it in the citation. Instead, simply cite the year of publication immediately after:

Fry (2001) says that there are many approaches to referencing.

2. Citing a Work with Two or More Authors

For a source with two authors in Chicago author–date referencing, cite both names in the order they are listed, joined with the word ‘and’ (not ‘&’):

Two is the best number (Fry and Smith 1998).

For a source with three authors, use an Oxford comma before the last name:

Three is still a good number (Fry, Smith, and Connor 2011).

If a source has four or more authors, cite the first name followed by ‘et al.’:

It turns out that four is too many (Fry et al. 2017).

You should, however, still name all authors in the reference list.

3. Quoting Sources

To quote a source, give a page number or numbers after a comma:

He said it ‘exactly like this’ (Smith 1984, 23).

Fry (2001, 12–13) argues that ‘eyewitness accounts are unreliable.’

The first citation above shows us that the quote comes from page 23 of the source cited. The second shows us that the quote comes from pages 12–13.

4. Two Works by the Same Author from the Same Year

If you cite two sources by the same author from the same year, a year of publication alone won’t be enough to show which source you’re citing. In this situation, then, you should add a letter after the year for each source that you cite in your work. For example:

Fry (1990a) originally worked on déjà vu. But he later examined the sense of having already lived through a present moment (Fry 1990b).

In the passage above, we cite two sources by ‘Fry’ from 1990. We have therefore added the letters ‘a’ and ‘b’ to show that they are distinct texts.

The correct letter to use will depend on the text’s position in your reference list. Sources from the same author and year should be ordered alphabetically by title here. You will then add ‘a’ after the first, ‘b’ after the second, etc.

Fry, John. 1990a. Déjà Vu and You. New York: Simon & Schuster.

———. 1990b. False Recollections. New York: Penguin Press.

Make sure the letters in citations match those used in the reference list.

5. Two Authors with the Same Surname

To cite two authors with the same surname, include first initials in citations:

The Earth revolves around the Sun (J. Smith 2004). However, people once believed that the Sun revolved around the Earth instead (R. Smith 1992).

You should list the authors with first names in full in the reference list, however, just like you would with any other author.

6. Citing More than One Source at Once

You can also cite more than one source in a single citation. To cite two or more sources by a single author at once, for example, you would simply add a comma between the years of publication:

Studies have shown the Earth is not flat (Smith 1971, 1982, 2006).

Here, we’ve cited three sources by ‘Smith’ all at once. You can also cite two or more sources by different authors. To do this, use a semicolon between each author’s surname:

Some people still believe in a flat Earth (Fry 2015; Smith 2006).

Names in a citation can be ordered alphabetically, chronologically, or by importance. It is simply a matter of clarity and preference. Here, we’ve ordered them alphabetically.