TY  - BOOK
AU  - Shasha, Dennis
TI  - Codes puzzels and conspiracy
SN  - 0-7176-2314-X
U1  - 793.74 SHA'C 
PY  - 1992///
CY  - NEWYORK
PB  - W. H. FREEMAN
KW  - MATHEMATICAL RECREATIONS
ER  -