TY  - BOOK
AU  - Houghton , Bernard  .
TI  - On-line information retrieval systems an introductory manual to principles and practice / 
SN  - 0-208-01660-0
U1  - 2:51(BV) 
PY  - 1977///
CY  - London : 
PB  - Clive Bingley Ltd , 
KW  - Library science- information system
ER  -