Subject
5 free books about proofreading, free to read online. Chapter 1 of any book is free, no account needed.
Hand-book of punctuation: With Instructions for Capitalization, Letter-writing, and Proof-reading
William Johnson Cocker
"Stops", Or How to Punctuate A Practical Handbook for Writers and Students
Paul Allardyce
The Importance of the Proof-reader A Paper read before the Club of Odd Volumes, in Boston, by John Wilson
John Wilson
Manual of Style Governing Composition and Proof Reading in the Government Printing Office
United States. Government Printing Office
Proof-Reading A Series of Essays for Readers and Their Employers, and for Authors and Editors
F. Horace Teall
