There’s a book on Amazon here:
It’s not a *great* book, the code is buggy, the A* implementation (which should be the corner-stone of a book on RTS games, is/was inclusive of a recursive depth-check Hack). I think the author got a fair amount of critique on that one, and is working (last I heard) on a second edition, and/or updates to the code.
That aside, if your looking to quickly get up to speed with the more technical implementations surrounding RTS games, this is a pretty cheap and cheerful implementations.
Oh, and there’s UML class diagrams in there too (a very good thing).