not sure what you mean by good. The standard books on quadratic forms over number fields are in Hanke's references. I would add that Hanke studied under Shimura, so you should take a look at shimura_2010 and shimura_2012, as the standard interplay is quadratic forms and modular forms. Note that the book that defined notation for a generation is O'Meara, in Hanke's references. I'm not sure Hanke mentions Kitaoka.
For other classical groups, Grove is unusual in including characteristic 2 in full detail.
Finally, i never got interested in using number fields. So i like Cassels, Rational Quadratic Forms.
Added in proof: take a look at THIS and THIS, maybe you will like something.