The Chicago Manual of Style Online
Consists of the online Chicago Manual of Style, 17th ed. (August 2017). Also includes the 16th ed. (2010), Chicago Style Q & A, Chicago-Style Citation Quick Guide, and related resources to assist in manuscript preparation.
The Chicago Manual of Style Online presents two basic documentation systems, the humanities style (notes and bibliography) and the author-date system. Choosing between the two often depends on subject matter and nature of sources cited, as each system is favored by different groups of scholars.
The humanities style is preferred by many in 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.