TY  - BOOK
AU  - Creswell, John W.
TI  - Research design : qualitative, quantitative, and mixed methods approaches 
SN  - 1412965576
PY  - 2009///
CY  - Los angeles
PB  - Sage Publications
KW  - Social sciences
KW  -  Research
KW  -  Methodology
KW  - Statistical methods
N1  - Includes bibliographical, references (p. 237-245) and indexes
ER  -