APA (7th ed.) Citation

Heidegger, M., Boss, M., Mayr, F., & Askay, R. (2001). Zollikon Seminars: Protocols - conversations - letters. Northwest University Press.

Chicago Style (17th ed.) Citation

Heidegger, Martin, Medard Boss, Franz Mayr, and Richard Askay. Zollikon Seminars: Protocols - Conversations - Letters. Evanston, Illinois: Northwest University Press, 2001.

MLA (8th ed.) Citation

Heidegger, Martin, et al. Zollikon Seminars: Protocols - Conversations - Letters. Northwest University Press, 2001.