DEFINITION: This formatting style consists of two separate documentation systems, notes and bibliography (called the “NB” system) used in the humanities field and author-date, preferred by the sciences. A writer’s choice between the two depends on the topical matter and the nature of the sources cited; each of the systems is preferred by different groups of scholars. The humanities style is preferred by many in the history, literature and arts. Bibliographic information is presented in notes and often in an actual bibliography. It is capable of supporting a number of sources, including those that are less prone to being included in the author-date formatting style.

The author-date system is more concise and generally used in the physical, natural, and social sciences disciplines. Sources here are parenthetically cited in the text using the author’s last name and publication date. The citations are expanded in a list of references, where full bibliographic information is provided.

PHYSICAL SET-UP: Use 8½” x 11.0” paper with a 1.0” margin on all sides (top, bottom, left and right). The paper is separated into three parts: (1) the front (title page, copyright page, dedication and/or epigraph, table of contents, illustrations, tables, abstract, acknowledgments, etc.); (2) the body including the text; and (3) the reference materials (appendixes, endnotes, bibliography or references, glossary, index, etc.). Text should be double-spaced but indented block quotes are single-spaced. Bibliographies, footnotes, and itemized lists should also be single spaced.

FOOTNOTES/END NOTES: If using the NB system, include a footnote or endnote each time a direct or a paraphrased quote is used as a source. At the end of a page footnotes will be added where the source is referenced, and either at the end of each chapter or the whole essay endnotes will be compiled. A footnote or endnote begins with the appropriate number followed by a period and then a space. The author/date system, prevalent in the natural and social science disciplines, inserts a reference to a different work within a set of parentheses. These contain the author, the date of publication and page reference, if appropriate.

A source is linked to a bibliographic reference with a superscript number. It is placed in the body of the essay following the end of the sentence in which the source is referenced. The initial reference of a source includes all relevant information; subsequently citing the same source requires only the author’s last name, shortened title of the work cited and appropriate page number or numbers.

This is how an in-text citation would appear in Chicago style:

The manufacturer recommends that the throttle gear is firmly secured against the wheel to prevent slippage when the motor is engaged.5
The footnote for the above in-text citation would appear below a line at the bottom of the same page:
___________________

5 Bill Emerson, Engine Maintenance, (Duluth: Pembroke, Derby and Fenwick, 1999),56.

BIBLIOGRAPHY: Since two formatting systems are used in Chicago style, the following code explains how they are referenced below:

N = Note
B = Bibliography entry
I = In-text Citation
R = Reference list entry

Some of the bibliographic formats for the more common reference materials are shown below:

Book

Real Example

N: 4. Kevin Delavan, Lassos and Rope Tricks, (Carson City: Wild Bill Publications, 2005), 78.
B: Delavan, Kevin, Lassos and Rope Tricks, Caron City: Wild Bill Publications, 2005.
I: (Delavan, 2005, 78)
R: Delavan, Kevin, 2005, Lassos and Rope Tricks, Caron City: Wild Bill Publications.

Journal

Real example

N: 9. James Murphy, “Crimes,” Police Work, 101 (2004): 45.
B: Murphy, James, “Crimes,” Police Work, 101 (2004): 45.
I: (Murphy 2004, 45)
R: Murphy, James, 2004, Police Work, 101 (2004): 45.

Web Site

Real Example

N: 2. Smith Dairies, “Milk Products,” Smith and Family Dairy Products, http://www.cowsforever.org/milk/memphis/10045/html
B: Smith Dairies, “Milk Products,” Smith and Family Dairy Products, http://www.cowsforever.org/milk/memphis/10045/html (accessed December 31, 2009).
I: (Smith Dairies)
R: Smith Dairies, Milk Products, Smith and Family Dairy Products, http://www.cowsforever.org/milk/memphis/10045/html