Taylor, S. J., Bodgan, R., & DeVault, M. L. (2015). Introduction to qualitative research methods: A guidebook and resource. John Wiley & Sons, Incorporated. Read Chapter 1.
Yin, R. K. (2018). Case study research and applications: Design and methods (6th ed.). SAGE Publications, Inc. This chapter focuses on data collection procedures and analytical strategies used in case study research.
Edmonds, A. & Kennedy T. D. (2017). An applied guide to research designs: Quantitative, qualitative, and mixed methods, Second Edition. SAGE Publications, Inc.