TY  - BOOK
AU  - Gardner, Martin
TI  - Codes, ciphers, and secret writing
SN  - 9780486247618
U1  - 001.54 GAR 
PY  - 1972///
CY  - New York
PB  - Dover Publications
KW  - Ciphers
KW  - Cryptography
KW  - Geheimschrift
ER  -