Tull, D. S. (1993). Marketting Research/6e (6th ed.).
Chicago Style aipamenaTull, Donald S. Marketting Research/6e. 6th ed. PHI, 1993.
MLA aipamenaTull, Donald S. Marketting Research/6e. 6th ed. 1993.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.