ashtray site is another extremely valuable reference

http://nevadacasinoashtrays.org/

Mark Englebretson put the site together (with some assistance), and he has TONS of pictures of ashtrays and casinos, operating dates, and casino history for a lot of Nevada casinos. His site doesn't list Eugene's, but it does list the Circle RB.

And I agree with Charles, Dwayne Kling's book is a "must have" for anyone interested in Reno.