Παραπομπή APA

Bernard, D. (1977). Charging For Computer Services: Principles and Guidelines. Petrocell.

Παραπομπή Chicago Style

Bernard, Dan. Charging For Computer Services: Principles and Guidelines. New York: Petrocell, 1977.

Παραπομπή MLA

Bernard, Dan. Charging For Computer Services: Principles and Guidelines. Petrocell, 1977.