COOPER D R. (2000). BUSINESS RESEARCH METHODS (6TH.). TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED.
Chicago-čujuhus (17. p.)COOPER D R. BUSINESS RESEARCH METHODS. 6TH. NEW DELHI: TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 2000.
MLA-čujuhus (9. p.)COOPER D R. BUSINESS RESEARCH METHODS. 6TH. TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 2000.
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