TY  - BOOK
AU  - Sayers Anthony P
TI  - Operation systems survey  
T2  - Petrocelli charter computer sceince series
U1  - X:89M0bD65,(B), L1 
PY  - 1971///
CY  - New York
PB  -   Petrolelli Charer        
KW  - ECONOMICS
ER  -