APA
Cooper D. R., . (2011). Business reasearch methods, 11th ed. [Place of publication not identified]: McGraw-Hill Irwin.
Chicago
Cooper Donald R, . 2011. Business reasearch methods, 11th ed. [Place of publication not identified]: McGraw-Hill Irwin.
Harvard
Cooper D. R., . (2011). Business reasearch methods, 11th ed. [Place of publication not identified]: McGraw-Hill Irwin.
MLA
Cooper Donald R, . Business reasearch methods, 11th ed. [Place of publication not identified]: McGraw-Hill Irwin. 2011.