Wills, G. (1967). Marketing through research ([1st ed.].). Pergamon Press.
Lua i Stíl Chicago (17ú heag.)Wills, Gordon. Marketing Through Research. [1st ed.]. Oxford, New York: Pergamon Press, 1967.
Lua MLA (8ú heag.)Wills, Gordon. Marketing Through Research. [1st ed.]. Pergamon Press, 1967.
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