The Chicago Manual of Style presents two basic documentation systems: (1) notes and bibliography and (2) author-date. Choosing between the two often depends on subject matter and the nature of sources cited, as each system is favored by different groups of scholars.
The notes and bibliography style is preferred by many in the humanities, including those in literature, history, and the arts. This style presents bibliographic information in notes and, often, a bibliography. It accommodates a variety of sources, including esoteric ones less appropriate to the author-date system.
The author-date system has long been used by those in the physical, natural, and social sciences. In this system, sources are briefly cited in the text, usually in parentheses, by author’s last name and date of publication. The short citations are amplified in a list of references, where full bibliographic information is provided.
Aside from the use of notes versus parenthetical references in the text, the two systems share a similar style. Click on the tabs below to see some common examples of materials cited in each style, including examples of common electronic sources. For numerous specific examples, see chapters 14 and 15 of the 16th edition of The Chicago Manual of Style.