Gaya APA

Harahap, S, S., Futrell, C. (1988). Sales Mangement (Ed. 2). USA : by The Dryden Press.

Gaya MLA

Harahap, Sofyan, Syafri., Futrell, Charles. "Sales Mangement". Ed. 2 USA : by The Dryden Press, 1988. Text.