Benbasat, I., Goldstein, D. K., & Mead, M. (1987). The Case Research Strategy in Studies of Information Systems MIS Quarterly, 11. Retrieved from http://links.jstor.org/sici?sici=0276-7783\%28198709\%2911\%3A3\%3C369\%3ATCRSIS\%3E2.0.CO\%3B2-P (Original work published 1987)