@book{39,
	author = {Hamel, Jacques, and Dufour, Stéphane,},
	title = {Case study methods /},
	publisher = {Sage Publications,},
	year = {c1993.},
	address = {Newbury Park :},
	url = {http://www.loc.gov/catdir/enhancements/fy0655/93026644-d.html}
}