Introductory Combinatorics 5th Edition by Richard A. Brualdi ISBN-13: 9780134689616This trusted best-seller covers the key combinatorial ideas?including the pigeon-hole principle, counting techniques, permutations and combinations, P?lya counting, binomial coefficients, inclusion-exclusion principle, generating functions and recurrence relations, combinatortial structures (matchings, designs, graphs), and flows in networks. The 5th Edition incorporates feedback from users to the exposition throughout and adds a wealth of new exercises.