The best single book is Anderson's book on ashtrays, John. It has a paragraph or two on each of the Nevada clubs it lists ashtrays from.

It's available from most any of the dealers who have chip books, including CT Coins in Cal;ifornia (800-50POKER).

CASINOS AND THEIR ASHTRAYS, A COLLECTOR'S GUIDE
Art Anderson, 1994

Price is about $20

DonL