Ruffin, Roy J. <br/><br/>
Principles of Microeconomics / 
Roy J. Ruffin, Paul R. Gregory 
 - Forth edition. 
 - New York :  Harper Collins College Publishers,  1989. 
 - xxxi, 485 pages :  illustrations ;  25 cm. 
<br/><br/> Includes Index. 
<br/><br/><label>ISBN: </label>0673460223 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Economics
<br/><br/><label>Dewey Class. No.: </label>338.5  / RUF