APA (7th ed.) Citation

Black, C. E., & Helmreich, E. C. (1959). Twentieth century Europe: A history (2nd ed., rev.). Knopf.

Chicago Style (17th ed.) Citation

Black, Cyril Edwin, and Ernst Christian Helmreich. Twentieth Century Europe: A History. 2nd ed., rev. New York: Knopf, 1959.

MLA (9th ed.) Citation

Black, Cyril Edwin, and Ernst Christian Helmreich. Twentieth Century Europe: A History. 2nd ed., rev. Knopf, 1959.