COOPER DONALD R. (2006). BUSINESS RESEARCH METHODS (9TH.). TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED.
Chicago-čujuhus (17. p.)COOPER DONALD R. BUSINESS RESEARCH METHODS. 9TH. NEW DELHI: TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 2006.
MLA-čujuhus (9. p.)COOPER DONALD R. BUSINESS RESEARCH METHODS. 9TH. TATA MCGRAW-HILL PUBLISHING COMPANY LIMITED, 2006.
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