WEIERS, R. (1988). Marketing Research Ronald M. Weiers. Prentice-Hall.
Lua i Stíl Chicago (17ú heag.)WEIERS, Ronald. Marketing Research Ronald M. Weiers. Prentice-Hall, 1988.
Lua MLA (8ú heag.)WEIERS, Ronald. Marketing Research Ronald M. Weiers. Prentice-Hall, 1988.
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