Case study as a research method - some resource

The following resources are on the topic of Case Study as a Research Method:

1. Basic description: http://en.wikipedia.org/wiki/Case_study
2. How to do case study research (pdf): http://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1001&context=nursing_faculty_pubs
3. Working paper on explanation (pdf): http://eprints.utm.my/8221/1/ZZainal2007-Case_study_as_a_Research.pdf