Ruffin, Roy J. <br/><br/>
Principles of Economics 

 - 4th ed. 
 - [S.l.] :  Longman,  1989 
<br/><br/><label>ISBN: </label>0673460207 (paperback) | 9780673460202 (paperback) 
<br/><br/><label>Dewey Class. No.: </label>330 RUF-P