Ruffin, J. Roy <br/><br/>
Modern price theory / 
Roy J. Ruffin 
 - London :  Scott, Foresman and Company,  1988       
 - xvi, 523 p. 
<br/><br/><label>ISBN: </label>067315985X 
<br/><br/><label>LC Class. No.: </label>HB 172 R932m 1988