Chicago citation style was created by the University of Chicago.  It is commonly used for citing sources in History and occasionally in the Humanities, Sciences, and Social Sciences. Chicago style has two formats:

• The Notes and Bibliography style is preferred by many in humanities disciplines, including history, literature, and the arts. Citations are provided in footnotes or endnotes and are usually accompanied by a bibliography.
• The Author-Date style (sometimes called "Reference List" style) is recommended for the physical, natural, and social sciences. Sources are cited using parenthetical in-text citation and full details are provided in a reference or works cited list.

Turabian is the student version of The Chicago Manual of Style, aimed at high school and college students who are writing papers, theses, and dissertations that are not intended for publication. The Chicago Manual of Style is aimed at professional scholars and publishers. The two books are compatible; both are official Chicago style.