For a great comparison of tools, see the MIT LibGuide on citation management.
Most commonly used to cite sources in history, but occasionally used in the humanities, social sciences, and sciences
Two formats:
The Notes and Bibliography style is preferred by many in humanities disciplines. Citations are provided in footnotes or endnotes and are usually accompanied by a bibliography.
The Author-Date style (somtimes called "Reference List" style) is recommended for the physical, natural, and social sciences. Sources are cited using an in-text citation and full details are provided in a reference or works cited list.