Three books by Don Laubach and Mark Henckel:
Elk Talk 1987
Elk Hunter ??
Elk Tactics 1998
These are a combo of rifle and archery with a lot of emphasis on archery. I've found more good info in these books than all the others combined that I've read.( One is not quite as good as the others, but is still as good as any others I've seen. I think It's Elk Hunter, But I'm not sure.)
Got my copies at Capital Sporting Goods in Helena, Mt.
Try E.L.K., Inc.
P.O.Box 85
Gardiner, Mt.59030
Ph. 1-800-272-4355