Chicago style is most often used in history and a few other humanities disciplines. Chicago style can use parenthetical citations, footnotes, or endnotes.
Use the following style guides to learn how to format citations in Chicago style:
Purdue Online Writing Lab (OWL) Chicago Style Guide - This includes more in-depth help on how to cite sources in Chicago style, as well as how to properly format other parts of your paper (the title page, appendices, etc.).
Chicago Manual of Style Online - The official publication manual for Chicago style. If you can't find the answer to your citation question in one of the above style guides, check here.