APA (7th ed.) Citation

Lengyel, E. (1950). America's role in world affairs (Rev. ed.). Harper.

Chicago Style (17th ed.) Citation

Lengyel, Emil. America's Role in World Affairs. Rev. ed. New York: Harper, 1950.

MLA (9th ed.) Citation

Lengyel, Emil. America's Role in World Affairs. Rev. ed. Harper, 1950.