APA (7e ed.) Bronvermelding

Schiffman, S. (2008). The 25 sales skills they don`t teach at business school. massachusetts Adams Media Corp.

Chicago (17e ed.) Bronvermelding

Schiffman, Stephan. The 25 Sales Skills They Don`t Teach at Business School. [s.l]: massachusetts Adams Media Corp, 2008.

MLA (9e ed.) Bronvermelding

Schiffman, Stephan. The 25 Sales Skills They Don`t Teach at Business School. massachusetts Adams Media Corp, 2008.