Cohen, W. A. (1984). Direct response marketing: An enterprencurial approach. john wiley& sons.
Chicago Style aipamenaCohen, William A. Direct Response Marketing: An Enterprencurial Approach. New York: john wiley& sons, 1984.
MLA aipamenaCohen, William A. Direct Response Marketing: An Enterprencurial Approach. john wiley& sons, 1984.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.