Princeton has several online resources for style guides and citing sources available at the Citing Sources page These include:
CSE
Scientific Style and Format: the CSE Manual for Authors, Editors, and Publishers. 8th ed. Style Manual Committee, Council of Science Editors. Chicago: University of Chicago Press, 2014. (In print at Firestone Ready Reference T11 .S386 2014.)
The Chicago Manual of Style is available online. This reference book is normally tethered to the reference section of the library but it can be now consulted online at any time.