Παραπομπή APA

Roth, C. B. (1970). Secrets of closing sales (4th ed.).

Παραπομπή Chicago Style

Roth, Charles B. Secrets of Closing Sales. 4th ed. 1970.

Παραπομπή MLA

Roth, Charles B. Secrets of Closing Sales. 4th ed. 1970.