There are many videos on research methods uploaded onto youtube. Here is another good presentation by Graham Gibbs who teaches at the University of Huddersfield in the UK. I really like Gibbs' many online tutorials available through the Online Qualitative Data Analysis.
Crowe, S., Cresswell, K., Robertson, A., Huby, G., Avery, A., & Sheikh, A. (2011). The case study approach. BMC medical research methodology, 11(1), pp100-
Flyvbjerg, B. (2006). Five misunderstandings about case-study research. Qualitative inquiry, 12(2), pp. 219-245.
Thacher, D. (2006). The normative case study. American journal of sociology, 111(6), pp.1631-1676.
Tight, M. (2010). The curious case of case study: a viewpoint. International Journal of Social Research Methodology, 13(4) pp.329-339.