Houghton, Bernard. <br/><br/>
On-line information retrieval systems  : An introductory manual to principles and practice 
/ by Bernard Houghton and John Convey 
 - London:   Clive Bingley ,   1977. 
 - 160p. 
<br/><br/><label>ISBN: </label>0208016600 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Boolean logic<br/>Information retrieval<br/>Library science<br/>On-line access
<br/><br/><label>Dewey Class. No.: </label>025.302854  / HOU/O