Four Styles in One Guide (APA | MLA | Chicago/Turabian | CBE)
         Research & Documentation Online | by Diana Hacker

American Psychological Association (APA) Style
         APAStyle.org | from the APA Web Site
         Using APA Format | from OWL: Online Writing Lab Purdue University
         Social Sciences: Documenting Sources | from Hackers' Research and Documentation Online

CBE (Council of Biology Editors) Style
         The Council of Biology Editors (CBE) Style of Documentation in Science and Mathematics | from The New Guide to Writing Research Papers
         Sciences: Documenting Sources | from Hackers' Research and Documentation Online

Chicago/Turabian Style
         History: Documenting Sources | from Hackers' Research and Documentation Online

Modern Language Association (MLA) Style
         Modern Language Association (MLA) Style | from The New Guide to Writing Research Papers
         Using MLA Format | from OWL: Online Writing Lab Purdue University
         Humanities: Documenting Sources | from Hackers' Research and Documentation Online

Other Subject Disciplines and Formats
         AAA Style Guide | from the American Anthropological Association Web Site
         Citing Government Resources | compiled by Gloria Hylton
         Introduction to Basic Legal Citation (aka The Bluebook) | from the Cornell Law School