Zikmund, W. G. (2009). Essentials of Marketing Research. Cengage.
Lua i Stíl Chicago (17ú heag.)Zikmund, William G. Essentials of Marketing Research. Delhi: Cengage, 2009.
Lua MLA (9ú heag.)Zikmund, William G. Essentials of Marketing Research. Cengage, 2009.
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