Tull, D. S., & Hawkins, D. I. (1993). Marketing research: Measurement & method (6th ed.). PHI Learning.
Chicago Style aipamenaTull, Donald S., and Del I. Hawkins. Marketing Research: Measurement & Method. 6th ed. New Delhi: PHI Learning, 1993.
MLA aipamenaTull, Donald S., and Del I. Hawkins. Marketing Research: Measurement & Method. 6th ed. PHI Learning, 1993.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.