Zikmund, W. G. (2010). Essentials of marketing research fourth edition. South-Western Cengage Learning.
Lua i Stíl Chicago (17ú heag.)Zikmund, William G. Essentials of Marketing Research Fourth Edition. South-Western Cengage Learning, 2010.
Lua MLA (8ú heag.)Zikmund, William G. Essentials of Marketing Research Fourth Edition. South-Western Cengage Learning, 2010.
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