APA (7th ed.) Citation

Somervell, D. C. (1955). A history of the United States to 1941 (2nd ed.). W. Heineman.

Chicago Style (17th ed.) Citation

Somervell, David Churchill. A History of the United States to 1941. 2nd ed. London: W. Heineman, 1955.

MLA (9th ed.) Citation

Somervell, David Churchill. A History of the United States to 1941. 2nd ed. W. Heineman, 1955.