TY  - BOOK
AU  - Creswell,John W.
TI  - Research design: qualitative, quantitative, and mixed methods approches 
SN  - 1412965576 :
PY  - 2009///
CY  - London
PB  - SAGE
KW  - Social sciences
KW  - Research
KW  - Methodology
KW  - Statistical methods
ER  -