TY  - BOOK
AU  - Kahn,David
TI  - The codebreakers: the story of secret writing
AV  - Z103 .K28
U1  - 652.8 
PY  - 1967///]
CY  - New York
PB  - Macmillan
KW  - Cryptography
KW  - History
KW  - Cryptographers
N1  - Includes bibliographical references
ER  -