TY  - BOOK
AU  - Lum M D
ED  - US> Air Force. Office of Aerospace Research. Aeronautical Research Laboratory
TI  - Technical reports and technical notes: mathematical properties associated with combination locks
U1  - 629.13 
PY  - 1968///
CY  - Washington
PB  - Government Printing
KW  - Aeronautics
ER  -