I haven't looked though this yet, but it might be a good pickup. 

https://www.amazon.com/Complete-Guide-Buffalo-Nickels/dp/1880731711

Noted numismatic author, David W. Lange, has completely rewritten his classic reference book on Buffalo Nickels. His third and best edition yet, is fully updated with current pricing and new developments of this popular series. This all-new edition contains over 200 fully-illustrated pages, loaded with valuable information.