Churchill, G. A., Ford, N. M., & Walker, O. C. (1997). Sales force management (5th ed.). Irwin.

Churchill, Gilbert A., Neil M. Ford, and Orville C. Walker. Sales Force Management. 5th ed. Chicago: Irwin, 1997.

Churchill, Gilbert A., et al. Sales Force Management. 5th ed. Irwin, 1997.