These are good books for graph based algorithms, which may well be what you're looking for. But for a more proof based approach you could take a look at this:

These are good books for graph based algorithms, which may well be what you're looking for. But for a more proof based approach you could take a look at this: http://books.google.com/books?id=HuDFMwZOwcsC&printsec=frontcover&source=gbs_summary_r&cad=0#v=onepage&q=&f=false http://books.google.com/books?id=HuDFMwZOwcsC&printsec=f...