Purdue OWL Chicago Manual of Style 16th Edition
From Purdue's Online Writing Lab.
"covers a variety of topics from manuscript preparation and publication to grammar, usage, and documentation and has been lovingly called the “editors’ bible.”
Focuses primarily on one of the two CMS documentation styles: the Notes-Bibliography System (NB), which is used by those in literature, history, and the arts. The other documentation style, the Author-Date System, is nearly identical in content but slightly different in form..."