If you wish to learn frailing patrick costello you tube, very clear easy instruction, clawhammer [which is not frailing] again try you tube, in my opinion the youtube videos are better than books, however a good book forclawhammer is the art of the mountain banjo, art rosenbaum, centerstream, my advice is start with g tuning, then experiment with sawmill, double c and cgbd.
ken perlman clawhammer banjo are also good books, ther was a good instructional mike seeger Southern Banjo Styles - The Complete 3-DVD Set | Homespun.
as for bluegrass there are loads of you tube, books well how about Earl Scruggs and the 5-String Banjo, Banjo - Hal Leonard Online
The Banjo of Ralph Stanley : Mike Seeger ... - Book Depository,
ralph stanley played bluegrass and clawhammer, so that might suit you