Cita APA (7th ed.)

Billington, R. A. (1965). The American frontier (2nd ed.). Amer. Historical Assoc..

Cita Chicago (17th ed.)

Billington, Ray Allen. The American Frontier. 2nd ed. Wash.: Amer. Historical Assoc., 1965.

Cita MLA (8th ed.)

Billington, Ray Allen. The American Frontier. 2nd ed. Amer. Historical Assoc., 1965.