Cita APA (7a ed.)

Erdmann, C. (1977). The origin of the idea of crusade. Princeton University Press.

Cita Chicago Style (17a ed.)

Erdmann, Carl. The Origin of the Idea of Crusade. Princeton, New Jersey: Princeton University Press, 1977.

Cita MLA (8a ed.)

Erdmann, Carl. The Origin of the Idea of Crusade. Princeton University Press, 1977.