Tull,Donald S, & Hawkins,Del I. (1993). Marketing research: Measurement & method (6th ed.). Prentice-Hall of India Pvt. Ltd.
Dyfyniad Arddull ChicagoTull,Donald S, and Hawkins,Del I. Marketing Research: Measurement & Method. 6th ed. New Delhi: Prentice-Hall of India Pvt. Ltd, 1993.
Dyfyniad MLATull,Donald S, and Hawkins,Del I. Marketing Research: Measurement & Method. 6th ed. Prentice-Hall of India Pvt. Ltd, 1993.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.