Perry, William E. <br/><br/>
Managing systems maintenance 
William E. Perry 
 -  c.1981 
<br/><br/><label>ISBN: </label>0894350463 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Software maintenance	--MIS
<br/><br/><label>Dewey Class. No.: </label>005.1 PER