Dewey decimal classification 

 -  1971 
<br/><br/><label>Standard No.: </label>86,721 
<br/><br/><label>Source: </label> Reference Collections 
<br/><br/><label>Subjects--Topical Terms: </label><br/>LIBRARY SCIENCE
<br/><br/><label>Dewey Class. No.: </label>2:51M7, L1.1-.2(RR)