Is the 'case-study method' widely accepted as a methodology for a PhD in the business faculty?
What is the appropriate number of cases required in a PhD thesis?
Any sites/references/structure for writing up the methodology section using case-study approach?

"Is the 'case-study method' widely accepted as a methodology for a PhD in the business faculty"

YES

"What is the appropriate number of cases required in a PhD thesis?"

This cannot be answered generally. I employed a single-case study. More important is the process of defining units of analysis.

"Any sites/references/structure for writing up the methodology section using case-study approach?"

Probably one of the most often cited and "traditional" starting point is: Yin, R. K. (2003) Case study research and methods, 3rd edition, London:Sage

Many thanks

Sage advice. Yin's book on case study methodology is a good yarn.

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