Cita APA

Billington, R. A. (1967). Westward wxpansion: A history of the American frontier. New York: MacMillan.

Citación estilo Chicago

Billington, Ray Allen. Westward Wxpansion: A History of the American Frontier. New York: MacMillan, 1967.

Cita MLA

Billington, Ray Allen. Westward Wxpansion: A History of the American Frontier. New York: MacMillan, 1967.