The OWL at Purdue University provides guidance on how to cite sources using American Medical Association (AMA) Style, including examples for print and electronic sources.

AMA citation guide from New York Medical College Health Sciences Library.

Guide to the annotated bibliography process from Cornell University.

Examples of citations for business databases hosted by the Michigan State University Business Library.

Examples of print and electronic resource citation from Purdue University.

The CAS Source Index (CASSI) Search Tool is an online resource intended to support researchers and librarians who need accurate bibliographic information. This resource can be used to quickly look up or confirm publication titles and abbreviations, as well as CODEN, ISBN, or ISSN codes. The CASSI database contains a listing of publications indexed by Chemical Abstracts Service (CAS) since 1907.

This site contains contains a link to a pdf of the Harvard Business School Citation Guide, which uses the Chicago Manual of Style to show footnotes and citations for annual reports, SEC filings, cases, databases, and many other business-related resources. 

Examples of print and electronic source citations from the Chicago Manual of Style.

Examples of print and electronic source citations for Chicago Manual of Style from Purdue University.

Overview, examples, and samples of APA and MLA literature reviews from Purdue University.

Guide to in-text citations and works cited examples using MLA 8th edition from Williams College.

Examples of business citations using MLA hosted by the Maag Library.

Examples of print and electronic source citations from Purdue University.

This is the official format for PNAS. See the Manuscript Format section and scroll down to References for details.

This site includes print and online source citation examples hosted by the Georgetown University Library.

Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research. Available for Windows and Mac.