TY  - BOOK
AU  - Andreescu, Titu  .
TI  - Path to combinatorics for undergraduates : countings strategies / 
SN  - 978-0-8176-4288-4
U1  - B3 
PY  - 2004///
CY  - Berlin : 
PB  - Birkhauser , 
KW  - Combinatorial number theory
ER  -