# The Chicago Manual of Style: author-date

Printable version of The Chicago Manual of Style: author-date (PDF).

The Chicago Manual of Style has two styles: one that uses endnotes and footnotes, and one that uses parenthetical citations. See our Chicago Style footnotes and endnotes resource if your discipline uses endnotes and footnotes.

The Chicago Manual of Style is a reference and style guide that uses the author-date system. It is most often used in the physical, natural, and social sciences.

For information on the citation format for sources not covered in this guide, refer to The Chicago Manual of Style, 16th ed.

## Documenting sources

Sources must be documented in two places: in parenthetical references and in a reference list.

## Parenthetical citations: Guidelines

Insert a citation when you use a direct quote, paraphrase information, or need to add further explanation to your text. Citations are placed in parentheses after a natural pause in meaning, but as close to the information as possible. Therefore, citations may appear in the middle of a sentence.

In-text citations tell readers exactly where you found specific information. Because they are meant to reflect the location of your evidence, they can contain the citation information for more than one source. See the final example in the sample below.

## Sample paragraph

In the 1840s, a camera cost only $5, but developing images was prohibitively expensive, and only those above the middle class could participate in the hobby (Seiberling and Bloore 1965, 57). The financial constraints of daguerreotype photography forced all Canadian practitioners to engage with the medium as an occupation instead of as a hobby (Greenhill 1965, 22), and in spite of the high costs, many entrepreneurs saw photography as a potentially profitable endeavour. To offset the cost of production, Canadian daguerreotype photographers charged an exorbitant amount, typically ranging between$3 and \$5 for one image, making it a luxury item only available to wealthy individuals such as John A. Macdonald or Louis Joseph Papineau, both of whom sat for portraits (Greenhill and Birrell 1979, 25; Skidmore 1996).

## Reference list: Guidelines

The reference list is a list of all material you consulted for your project, even if you did not cite it in your text. Sources are listed alphabetically in a section titled “Reference List” that is placed at the very end of your assignment.

## Citation Format for Different Types of Sources

Remember that page numbers are not always necessary. For example, citations for ebooks generally do not require page numbers.

What to do when reference list information is missing:

• Missing author: Cite by title
• Missing publisher: Use n.p. in place of the publisher
• Missing date: Use n.d. in place of the date
• Missing place of publication: Use n.l. in place of the location

## Sample reference list

Please note that a reference list will always occur on its own page.

The following link provides a sample reference list (PDF)

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