Gaya APA

Zaiss, C, D., Gordon, T. (1993). Sales Effectiveness Training: the Breakthrough Method to Become Partners with Your Customers . New York: Penguin Groups.

Gaya MLA

Zaiss, Carl, D.., Gordon, Thomas. "Sales Effectiveness Training: the Breakthrough Method to Become Partners with Your Customers". New York: Penguin Groups, 1993. Texts.