APA (7th ed.) Citation

Hamel, J., Dufour, S., Fortin, D., & Dufour, S. (1993). Case study methods. Qualitative research methods.

Chicago Style (17th ed.) Citation

Hamel, Jacques, Stéphane Dufour, Dominic Fortin, and Stéphane Dufour. "Case Study Methods." Qualitative Research Methods 1993.

MLA (8th ed.) Citation

Hamel, Jacques, et al. "Case Study Methods." Qualitative Research Methods, 1993.