APA (7th ed.) Citation

Heidegger, M., Jaspers, K., & Biemel, W. (1990). Briefwechsel: 1920 - 1963. Klostermann.

Chicago Style (17th ed.) Citation

Heidegger, Martin, Karl Jaspers, and Walter Biemel. Briefwechsel: 1920 - 1963. Frankfurt am Main: Klostermann, 1990.

MLA (8th ed.) Citation

Heidegger, Martin, et al. Briefwechsel: 1920 - 1963. Klostermann, 1990.