TY  - BOOK
AU  - Wallis, W. D.
AU  - George, J. C.
TI  - Introduction to combinatorics
T2  - Dicrete Mathematics and its Application
SN  - 9781439806227
U1  - 511.6 
PY  - 2011///
CY  - New York
PB  - CRC Press
ER  -