Gaya APA
Gresswell, J, W. (2003).
Research Design, Qualitative, Quantitative and Mixed Methods Approach- 2nd Edition .
London:
Sage Publications.
Gaya MLA
Gresswell, John, W.
"Research Design, Qualitative, Quantitative and Mixed Methods Approach- 2nd Edition".
London:
Sage Publications,
2003.
Text.