TULL DONALD S. (1976). MARKETING RESEARCH MEANING MEASURMENT & METHOD.TEXT WITH CASES. MACMILLAN.
Lua i Stíl Chicago (17ú heag.)TULL DONALD S. MARKETING RESEARCH MEANING MEASURMENT & METHOD.TEXT WITH CASES. NEW YORK: MACMILLAN, 1976.
Lua MLA (9ú heag.)TULL DONALD S. MARKETING RESEARCH MEANING MEASURMENT & METHOD.TEXT WITH CASES. MACMILLAN, 1976.
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