Cita APA (7a ed.)

Keylor, W. R. (1984). The twentieth-century world: An international history. Oxford University Press.

Cita Chicago Style (17a ed.)

Keylor, William R. The Twentieth-century World: An International History. New York [etc.]: Oxford University Press, 1984.

Cita MLA (9a ed.)

Keylor, William R. The Twentieth-century World: An International History. Oxford University Press, 1984.