The Cambridge Guide to English Usage
The Chicago Guide to Grammar, Usage, and Punctuation
The Columbia Guide to Standard American English
A Dictionary of Modern English Usage
The Little Red Writing Book: Two Winning Books in One, Writing Plus Grammar
May I Quote You on That? A Guide to grammar and Usage
One Day in the Life of the English Language: A Microcosmic Usage Handbook
The Oxford Dictionary of English Grammar
The Oxford English Dictionary Online
Pocket Fowler's Modern English Usage
When Bad Grammar Happens to Good People: How to Avoid Common Errors in English
