The following sites can provide some useful guidelines for citing resources.

APA Style:

• Electronic Reference Formats (from the APA web site)
  
• APA Publication Manual Crib Sheet
  
• Web Extensions to APA Style
• Social Sciences: Documenting Sources by Diana Hacker. It provides a general overview of APA style, including how to cite print resources.

Chicago Style:

• History: Documenting Sources by Diana Hacker. It provides a general overview of Chicago style, including how to cite print resources.

• Sciences: Documenting Sources by Diana Hacker. It provides a general overview of CSE style, including how to cite print resources.

• Citing WWW Sources (from the MLA web site)
  
• Humanities: Documenting Sources by Diana Hacker. It provides a general overview of MLA style, including how to cite print resources.

Turabian:

• Brief Citation Guide for Internet Sources in History and the Humanities