Cita APA (7a ed.)

Freud, S., Zweig, A., Freud, E. L., Robson-Scott, E., & Robson-Scott, W. D. (1970). The letters of Sigmund Freud and Arnold Zweig. Harcourt Brace Jovanovich, Inc.

Cita Chicago Style (17a ed.)

Freud, Sigmund, Arnold Zweig, Ernst L. Freud, Elaine Robson-Scott, y William Douglas Robson-Scott. The Letters of Sigmund Freud and Arnold Zweig. New York: Harcourt Brace Jovanovich, Inc, 1970.

Cita MLA (9a ed.)

Freud, Sigmund, et al. The Letters of Sigmund Freud and Arnold Zweig. Harcourt Brace Jovanovich, Inc, 1970.