APA (7th ed.) Citation

Feuerbach, L., Niebuhr, H. R., & Barth, K. (1957). The essence of christianity. Harper & Row Publichers.

Chicago Style (17th ed.) Citation

Feuerbach, Ludwig, H. Richard Niebuhr, and Karl Barth. The Essence of Christianity. New York [etc.]: Harper & Row Publichers, 1957.

MLA (9th ed.) Citation

Feuerbach, Ludwig, et al. The Essence of Christianity. Harper & Row Publichers, 1957.