Zikmund, W. G., & Babin, B. J. Essentials of marketing research (4th ed.).
Cita Chicago (17th ed.)Zikmund, William G., i Barry J. Babin. Essentials of Marketing Research. 4th ed.
Cita MLA (8th ed.)Zikmund, William G., i Barry J. Babin. Essentials of Marketing Research. 4th ed.
Atenció: Aquestes cites poden no estar 100% correctes.