APA (7th ed.) Citation

Bormann, M., Bormann, G., & Trevor-Roper, H. R. (1981). The Bormann letters. AMS Press.

Chicago Style (17th ed.) Citation

Bormann, Martin, Gerda Bormann, and H. R. Trevor-Roper. The Bormann Letters. New York: AMS Press, 1981.

MLA (9th ed.) Citation

Bormann, Martin, et al. The Bormann Letters. AMS Press, 1981.