Ellis, David <br/><br/>
Progress and problems in information retrieval /  
David Ellis 
 - 2nd ed. 
 - London :  Library Association,  1996 
 - 220 p. :   ill. ;   25 cm. 
<br/><br/>p. 192-213 
<br/><br/><label>ISBN: </label>1856041239  RM117.85 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Information storage and retrieval systems<br/>Information retrieval