Cita APA (7th ed.)

Nichols, J. P. (1943). Twentieth century United States: A history. D. Appleton-Century.

Cita Chicago (17th ed.)

Nichols, Jeanette Paddok. Twentieth Century United States: A History. New York: D. Appleton-Century, 1943.

Cita MLA (9th ed.)

Nichols, Jeanette Paddok. Twentieth Century United States: A History. D. Appleton-Century, 1943.