APA (7th ed.) Citation

Ott, U., Pfäfflin, F., & Siefken, H. (1989). Theodor Haecker: 1879-1945.

Chicago Style (17th ed.) Citation

Ott, Ulrich, Friedrich Pfäfflin, and Hinrich Siefken. Theodor Haecker: 1879-1945. Marbach, 1989.

MLA (8th ed.) Citation

Ott, Ulrich, et al. Theodor Haecker: 1879-1945. 1989.