Cosby, Paul C. <br/><br/>
Methods in Behavioral research 
Cosb 
 - 8e. 
 - Boston :  McGraw-Hill,  2005 
 - xi, 396. 
<br/><br/><label>ISBN: </label>0-07-252342-5 
<br/><br/><label>LC Class. No.: </label>BF 765 .C69 2004