TY  - GEN
AU  - Wallis, W D 
AU  - George, J.C
TI  - Introduction to combinatorics 
T2  - Discrete mathematics and its applications
SN  - 9781439806227
PY  - 2011///
CY  - Boca Raton
PB  - Chapman & Hall/CRC
KW  - Combinatorial analysis
KW  - Graph theory
ER  -