TY  - BOOK
AU  - Wallis
AU  -  Wallis
TI  - Combinatrics: Room squares, sumfree sets, hadamard matrices
T2  - Lecture notes in mathematics; 292
U1  - B217, L2 
PY  - 1972///
CY  - Berlin
PB  - Springer-Verlaf         
KW  - Combinatorial Theory
ER  -