The Chicago Manual of Style presents two basic documentation systems, the humanities style (notes and bibliography) and the author-date system.
Notes-bibliography system (Humanities Style): preferred for literature, history, and the arts. Notes may be footnotes or endnotes. For notes, indent the first line; in the bibliography, indent the second and subsequent lines.
Author-date system: used in the physical, natural, and social sciences. Sources are cited in the text in parentheses, by author’s last name, date of publication and page number if needed. Full bibliographic information is provided in a list of references. In the reference list, indent the second and subsequent lines.