APA (7th ed.) Citation

Harnack, A. v., & Bultmann, R. K. (1957). What is Christianity? (1st Harper Torchbook ed.). Harper & Brothers.

Chicago Style (17th ed.) Citation

Harnack, Adolf von, and Rudolf Karl Bultmann. What Is Christianity? 1st Harper Torchbook ed. New York: Harper & Brothers, 1957.

MLA (9th ed.) Citation

Harnack, Adolf von, and Rudolf Karl Bultmann. What Is Christianity? 1st Harper Torchbook ed. Harper & Brothers, 1957.