Tull, D. S., & Hawkins, D. I. (1990). Marketing research (5th ed.). MacMillan.
Chicago Edition CitationTull, Donald S., and Del I. Hawkins. Marketing Research. 5th ed. United states: MacMillan, 1990.
MLA Edition CitationTull, Donald S., and Del I. Hawkins. Marketing Research. 5th ed. MacMillan, 1990.
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