Loseke, D. (2017). 2 foundations. In Methodological thinking: Basic principles of social research design (pp. 17-34). SAGE Publications. Read Chapter 2: “Foundations”
Babones, S. J. (2014). Variable operationalization. In Methods for quantitative macro-comparative research (pp. 51-76). SAGE Publications, Inc. Read Chapter 3: “Variable Operationalization”
Check, J., & Schutt, R. (2012). Science, schooling, and educational research. In Research methods in education (pp. 1-6). SAGE Publications. Read Chapter 1: “Science, Schooling and Educational Research”
Check, J., & Schutt, R. (2012). The process and problems of educational research. In Research methods in education (pp. 21-24). SAGE Publications, Inc.