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How to format citations

A source citation should enable the reader to find the passage you are citing in the source where you found it. There are two different ways to do this:

  1. Footnotes or endnotes;
  2. In-text citations (identifying the source using parenthetical references within your text).

Find out whether your instructor requires a particular style of citation. If the instructor has no preference, you may choose between various "citation styles" (sets of rules for how to format your citations). Some citation styles call for notes, and some call for in-text citations. A given citation style will also give you guidelines for formatting a bibliography (or "works cited" list).

Choose one style for your paper and follow it consistently throughout. If you are using footnotes, then all of your citations should be placed in footnotes. No commonly accepted citation style allows you to combine footnotes or endnotes with parenthetical (in-text) references. Do not invent your own hybrid style!

Here is an overview of the most common styles, with links to models of each one:


Chicago Manual of StyleChicago Manual of Style (“Turabian”)

The Chicago Manual defines two distinct styles: Notes-Bibliography (N-B) and the less common Author-Date (A-D) style. (Chicago N-B style is sometimes just called "Chicago style", since it is the more commonly used of the two.)

Full guidelines and examples of both "Chicago styles" (N-B and A-D) are found in the Chicago Manual of Style and in Kate L. Turabian, A Manual for Writers of Research Papers, Theses, and Dissertations. Concise online overviews can be found here:

The Chicago Manual of Style Online also provides the full contents of the Chicago style guide in an easy-to-use online format. The full contents are available by subscription-only, but Calvin has a subscription; if you access the site via a computer on Calvin's network, you should be able to view the full text.

Chicago N-B (Notes-Bibliography) Style

This style is the most “formal” academic citation style, and is preferred by History, Philosophy, and other humanities disciplines that often require lengthy citations. Its main distinction from other styles is that it uses footnotes or endnotes for citations rather than putting them in the main body of the text. This allows for citations to be maximally detailed and to include commentary when needed. It also calls for a bibliography listing all sources cited.

Simple overviews and examples of Chicago N-B style can be found on these websites:

Chicago A-D (Author-Date) Style

This version of Chicago style uses in-text citations such as (Smith 2012) or (Jones 1976, 304) rather than footnotes. It is preferred by many natural sciences and social sciences. An overview is given in the American Political Science Association Style Manual (pp. 17ff).


MLAMLA (Modern Language Association)

This style is preferred by most literature departments, including English. It uses in-text citations rather than footnotes or endnotes, allowing for simpler citations and avoiding the complexity of notes.

Full guidelines and examples of “MLA style” are given in the MLA Handbook for Writers of Research Papers and the MLA Style Manual and Guide to Scholarly Publishing.

Simple overviews and examples can be found here:


APA (American Psychological Association)

This style also uses internal citations, and is preferred by most social science disciplines. Full guidelines and examples of “APA style” are given in the Publication Manual of the American Psychological Association.

Simple overviews and examples can be found here:


SBLSBL (Society for Biblical Literature)

This is a specialized citation style for Biblical Studies. Full guidelines and examples of the Society of Biblical Literature (SBL) style are given in The SBL Handbook of Style (SBLHS).

Summaries and examples are provided in:


Other online citation resources

You may also find the following resources useful for understanding the similarities and differences between the various citation styles: