Cooper, D. R., Schindler, P. S., & Sharma, J. K. (2011). Business research methods (11th ed.). McGraw-Hill Edcuation India.

Cooper, Donald R., Pamela S. Schindler, and J. K. Sharma. Business Research Methods. 11th ed. New Delhi: McGraw-Hill Edcuation India, 2011.

Cooper, Donald R., et al. Business Research Methods. 11th ed. McGraw-Hill Edcuation India, 2011.