Good books of protein data base searching?

[M.J. Lush]

	I am starting to do protein and DNA sequence data base 
searches and I would like to understand the background better 
can anyone suggest good clear books/reviews/papers on this subject.

	(I'm esp. interested in the subtlties of scoreing matrix)

-- 
Michael 
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NPC rights activist  | Nameless Abominations are people too!