Cita APA (7th ed.)

Beckman, P. R. (1984). World politics in the twentieth century. Prentice-Hall.

Cita Chicago (17th ed.)

Beckman, Peter R. World Politics in the Twentieth Century. Englewood Cliffs, New Jersey: Prentice-Hall, 1984.

Cita MLA (9th ed.)

Beckman, Peter R. World Politics in the Twentieth Century. Prentice-Hall, 1984.