Tull, Donald S. <br/><br/>
Marketing research / 
Donald S. Tull and Del I. Hawkins. 
 - 4th edition. 
 - New York :  McMillan Publishing Company,  1987. 
 - 835 pages ;  23 cm. 
<br/><br/> Includes index. 
<br/><br/><label>ISBN: </label>9711105098