Version: 16th ed.
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Chicago-style source citations come in two varieties:

  1. notes and bibliography,
  2. author-date.

The notes and bibliography system is preferred by many working in the humanities – including literature, history, and the arts. In this system, sources are cited in numbered footnotes or endnotes. Each note corresponds to a raised (superscript) number in the text. Sources are also usually listed in a separate bibliography. The notes and bibliography system can accommodate a wide variety of sources, including unusual ones that don’t fit neatly into the author-date system.

The author-date system is more common in the sciences and social sciences. In this system, sources are briefly cited in the text, usually in parentheses, by author’s last name and year of publication. Each in-text citation matches up with an entry in a reference list, where full bibliographic information is provided.

Aside from the use of numbered notes versus parenthetical references in the text, the two systems share a similar style.

Citation rules

In most cases, note numbers should be placed at the end of a sentence or clause, with the number following any punctuation (except for a dash, which it precedes). Order note numbers consecutively, beginning with 1 and continuing throughout the paper or article. Use superscript (superior) style for note reference numbers in the text (i.e. 1), and a normal full sized font for note reference numbers in the notes themselves, unless you are preparing a manuscript, in which case superscripted numbers may be used in both the text and the notes.

Subsequent citations of sources that have already been referenced should be documented in short form. Short form usually includes the author, editor or translator’s last name (omitting any abbreviations such as ed. or trans.), the main title of the work cited, plus any relevant page numbers. The short title omits A or The, includes the key word or words, and is italicized.

In Chicago Style, a bibliography is an alphabetical list of all of the sources cited in a work, as well as some which may not have been cited, but which support the work indirectly or provide relevant additional reading. The bibliography is usually placed at the end of the work. Arrange the works listed in a bibliography alphabetically by the author (or editor)’s last name, or if there is no author or editor, by the title of the work, or a keyword that a reader might use in attempting to search for the work.

In-text citation

(Thoreau 2016, 177–78)


(Grazer and Fishman 2015, 12)


(Chicago Manual of Style 2015)


Cooper, James Fenimore. The Last of the Mohicans; A Narrative of 1757. London: John Miller, 1826.
Serial / journal article (print)
Lundblad, Michael. "Epistemology of the Jungle: Progressive-Era Sexuality and the Nature of the Beast." American Literature 81, no. 4 (December 2009): 747-773.
Electronic resource (remote access)
Ward, Paul.  "Antarctica Fact File." Cool Antarctica. Last modified 2001.