Gaya APA

Creswell, J, W. (2003). Research design: qualitative, quantitative, and mixed methods approaches (2). Thousand Oaks, California: SAGE Publications Inc..

Gaya MLA

Creswell, John, W.. "Research design: qualitative, quantitative, and mixed methods approaches". 2 Thousand Oaks, California: SAGE Publications Inc., 2003. Text.