Cita APA (7a ed.)

Smith, N., & Hirst, M. (1991). The American frontier. Wayland.

Cita Chicago Style (17a ed.)

Smith, Nigel, y Mike Hirst. The American Frontier. Hove: Wayland, 1991.

Cita MLA (9a ed.)

Smith, Nigel, y Mike Hirst. The American Frontier. Wayland, 1991.