Churchill, Gilbert A. <br/><br/>
Sales force management :  planning, implementation, and control / 
Gilbert A. Churchill, Jr., Neil M. Ford, Orville C. Walker, Jr. 
 - 3rd ed. 
 - Homewood, IL :  Irwin,  c1990. 
 - xviii, 845 p. :  ill. ;  24 cm. 
 - The Irwin series in marketing .