University of Calgary
University of Calgary: Parentheses and Rules for Use
This site contains information regarding the correct usage of parentheses in original material and in quoted material. Examples are included for all points discussed.
SUNY Empire State College
Empire State College: Parentheses
This site contains information regarding the correct usage of parentheses, along with examples for each use.
Virginia Tech
Virginia Tech: Parentheses and Rules for Use
This resource contains five rules for correctly using parentheses and a section regarding capitalization within parentheses. Examples are included for each of the rules.
Other
Grammar Book: Parentheses and Brackets
Included on this site are three rules for correct usage of parentheses, along with examples for all of the rules, and a quiz.
Washington State University
Washington State University: Parentheses
This site from the Washington State University is designed to inform the reader of the most common errors regarding the use of parentheses.
University of Victoria (Canada)
The U Vic Writer's Guide: Grammar: Parentheses
This site contains information regarding the correct usage of parentheses, along with examples.