TY  - GEN
AU  - Welsh,Dominic
TI  - Codes and cryptography
SN  - 0198532881
U1  - 652.8 
PY  - 1988///
CY  - Oxford [Oxfordshire], New York
PB  - Clarendon Press, Oxford University Press
KW  - Ciphers
KW  - Cryptography
N1  - Cuprinde Index; Includes
ER  -