TY - BOOK AU - Creswell, John W. TI - Research design: qualitative, quantitative, and mixed methods approaches SN - 978-1-4129-6557-6 AV - H62.C6963 PY - 2009/// CY - London PB - SAGE Publication KW - Social science-Research-Methodology KW - Social sciences-Statistical methods N1 - Include bibliographical references and index ER -