Certo <br/><br/>
Supervision Concepts and Skill-Building / 

 - 6th ed. 
 - New York :  McGraw-Hill,  2008. 
 - xxx, 573 p. :  Col. ill. ;  25 cm 
<br/><br/><label>ISBN: </label>978007340500 
<br/><br/><label>Dewey Class. No.: </label>658.302/  / CER