1. Proofs That Really Count;Benjamin,2003
2. W.H. Beyer (Ed.), CRC Standard Mathematical Tables, 28th ed., CRC Press, Boca Raton, FL, 1987.
3. Enumerative Combinatorics;Charalambides,2002
4. Advanced Combinatorics;Comtet,1974
5. Combinatorial Identities;Gould,1972