COOPER D R. (2001). BUSINESS RESEARCH METHODS (6TH.). TATA MCGRAW-HILL PUBLISHING COMPANY.
Chicago-čujuhus (17. p.)COOPER D R. BUSINESS RESEARCH METHODS. 6TH. NEW DELHI: TATA MCGRAW-HILL PUBLISHING COMPANY, 2001.
MLA-čujuhus (9. p.)COOPER D R. BUSINESS RESEARCH METHODS. 6TH. TATA MCGRAW-HILL PUBLISHING COMPANY, 2001.
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