Other
Sta: Punctuation and Capitalization Rules
Use this handy guide for a quick reference to punctuation and capitalization rules. Includes rules for end marks, apostrophes, capitalization, commas, quotation marks, and many more!
Harvard University
Harvard Writing Center: Tips on Grammar, Punctuation and Style
Rather than lists of rules, this site provides practical advice on the use of commas, semicolons, dashes, hyphens, abbreviations, acronyms, split infinitives, "this," "that," italics, and underlining. CCSS.ELA-Literacy.CCRA.L.2