Approaches and Methodologies in Social Sciences: Della Porta, D. e Keating, M.2008Della Porta, D. e Keating, M. (2008) Approaches and Methodologies in Social Sciences. Cambridge: Cambridge University Press.
Designing Social Inquiry: Scientific Inference in Qualitative Research: King, G; Keohane, R, e Verba, S.1994King, G; Keohane, R. e Verba, S. (1994) Designing Social Inquiry: Scientific Inference in Qualitative Research. Princeton: Princeton University Press.
Doing Research in Political Science: An Introduction to Comparative Methods and Statistics: Pennings, P., Keman, H. e Kleinnijenhuis, J.2006Pennings, P., Keman, H. e Kleinnijenhuis, J. (2006) Doing Research in Political Science: An Introduction to Comparative Methods and Statistics, Londres: Sage
A tale of two cultures: Contrasting quantitative and qualitative research: Mahoney, J. e Goertz, G.2006Mahoney, J. e Goertz, G. (2006) A tale of two cultures: Contrasting quantitative and qualitative research, vol. 14 (3), 227-249