Kent, Allen. <br/><br/>
Encyclopedia of Library and Information Science Vol-21 /  

 - First Ed. /  
 - New York-10016 :   Marcel Dekker, Inc.. 
 - p.505 :  
<br/><br/><label>ISBN: </label>0-8247-2021-0 
<br/><br/><label>Dewey Class. No.: </label>2K  / K8.21