University of Calgary
Univ. Of Calgary: Punctuation Rules Periods
The informational site which includes helpful details concerning the rules, uses, and misuses of periods in the English language. Includes information about the period at the end of sentences as well as in abbreviations. Also, provides...
Rutgers University
Rutgers University: Guide to Grammar and Style: Periods
An excellent outline of the usage and rules concerning the "period" in English punctuation. Includes guidelines about acronyms, abbreviations, sentence ending, and more.
Capital Community College Foundation
Guide to Grammar and Writing: The Period
An excellent resource detailing the uses and rules of the grammatical element "the period." Also includes information about the period in sentences, quotation marks, parentheses, and abbreviations.
Other
Sandhills Community College: The Period
A good guide to understanding the several uses of the period in English punctuation. Includes information concerning periods in a sentence as well as abbreviations. Includes several examples.
University of Ottawa (Canada)
University of Ottawa: End Punctuation
Resourceful site which includes information about periods, question marks, and exclamation marks. Also provides examples and addresses abbreviation rules for periods.
University of Calgary
Univ. Of Calgary: Periods, Question Marks, Exclamations
This excellent resource provides information about rules, uses, and misuses of these three end marks (period, question mark, exclamation mark). Also, includes examples and short quizzes at the end of each section.