TY  - BOOK
AU  - Gardner, Martin
TI  - Penrose tiles to trapdoor ciphers : --and the return of Dr. Matrix
SN  - 9780883855218
SN  - 97070505
U1  - 793.73 GAR 
PY  - 1997///
CY  - Wsshington, DC
PB  - Mathematical Association of America
KW  - Mathematical recreations
N1  - Includes bibliographical references and index
ER  -