TY  - GEN
AU  - Zhang, Yao 
TI  - Combinatorial problems in mathematical  competitions 
T2  - (Mathematical olympiad)
SN  - 9789812839497
PY  - 2011///
CY  - Shanghai
PB  - East china normal university
KW  - Combinational analysis
KW  - Mathematical competitions
N1  - v.4
ER  -