APA (7th ed.) Citation

Paul, E., Paul, C., & Freud, S. (1921). A young girl's diary. T. Seltzer.

Chicago Style (17th ed.) Citation

Paul, Eden, Cedar Paul, and Sigmund Freud. A Young Girl's Diary. New York: T. Seltzer, 1921.

MLA (9th ed.) Citation

Paul, Eden, et al. A Young Girl's Diary. T. Seltzer, 1921.