APA (7th ed.) Citation

Freud, S., Zweig, A., & Freud, E. L. (1970). The letters of Sigmund Freud and Arnold Zweig. Harcourt, Brace & World.

Chicago Style (17th ed.) Citation

Freud, Sigmund, Arnold Zweig, and Ernst L. Freud. The Letters of Sigmund Freud and Arnold Zweig. New York: Harcourt, Brace & World, 1970.

MLA (8th ed.) Citation

Freud, Sigmund, et al. The Letters of Sigmund Freud and Arnold Zweig. Harcourt, Brace & World, 1970.