Cita APA (7th ed.)
Gretz, K. F. (1996). Professional selling: A consultative approach. Irwin.
Cita Chicago (17th ed.)
Gretz, Karl F. Professional Selling: A Consultative Approach. Chicago: Irwin, 1996.
Cita MLA (9th ed.)
Gretz, Karl F. Professional Selling: A Consultative Approach. Irwin, 1996.
Atenció: Aquestes cites poden no estar 100% correctes.