Van Rijsbergen, C. J. <br/><br/>
Information retrieval   
by C. J. Van Rijsbergen. 
 - London  Butterworths  1975 
 - 152p. 
<br/><br/><label>ISBN: </label>0408707178 
<br/><br/><label>Dewey Class. No.: </label>029.7  / N751