TY - BOOK AU - Creswell, John W. TI - Research design: qualitative, quantitative, and mixed methods approaches SN - 9781412965576 (pbk.) U1 - 300.72 PY - 2009/// CY - Thousand Oaks, CA PB - Sage Publications KW - Social sciences KW - Research KW - Methodology KW - Statistical methods ER -