Philosophy

General

• How to Cite Digitized Primary Sources (Library of Congress)  Examples in Chicago and MLA; how to cite electronic reproductions of primary sources, including film, photographs, legal and government publications, maps, recorded sound, text, and other special sources.
• Sources and Citations at Dartmouth at (Dartmouth College)  Not a style manual per se, but a writer's guide to academic integrity, citing sources, and evaluation of sources.

APA (American Psychological Association)

• APA Formatting and Style Guides (7th edition)  (6th edition) (Purdue Online Writing Lab)
• Citing Business Sources in APA Style (Fogler Guide)
• APA 7th Edition Citation Changes (Fogler Guide)

Chicago (Turabian) Style

• Chicago Manual of Style 17th Edition (Purdue Online Writing Lab)
• Ohio State University Guides to Chicago Style: Author-Date System, Notes-Bibliography System
• Turabian Quick Guide (U of Chicago Press)
• Chicago-Style Citation Quick Guide

MLA (Modern Language Association)

• MLA Style Center (MLA)
• MLA Formatting and Style Guide (Purdue Online Writing Lab)

Government and Legal Publications 

• Citing U.S. Government Publications (IU Indiana University Bloomington)
• Introduction to Basic Legal Citation (Cornell Law School)  Guide to citing judicial opinions, constitutions and statutes, arbitration, court rules, cases, etc. 

IEEE Citation Style

• IEEE Overview (Purdue Online Writing Lab)
• How to Cite References: IEEE Documentation Style (IEEE DataPort)
• IEEE Reference Guide (IEEE)

Other Forms

• ASA (American Sociological Association) Style (Purdue OWL)
• Council of Science Editors (Colorado State) 
• Council of Science Editors (CSE) Style Guide (Ohio State University)
• American Anthropological Association Style Guide
• Vancouver style  "...commonly used in medicine and science..."

Formatting Papers

• How to Format Your Research Paper
• Formatting in APA style (APA)
• Formatting in MLA style (Purdue OWL)