Cita APA (7th ed.)

Schaefer, L. F., Fowler, D. H., & Cooke, J. E. (1968). Problems in Western civilization: The challenge of history (Expanded two-volume ed.). Charles Scribner's Sons.

Cita Chicago (17th ed.)

Schaefer, Ludwig Frederick, David Henry Fowler, i Jacob Ernest Cooke. Problems in Western Civilization: The Challenge of History. Expanded two-volume ed. New York: Charles Scribner's Sons, 1968.

Cita MLA (9th ed.)

Schaefer, Ludwig Frederick, et al. Problems in Western Civilization: The Challenge of History. Expanded two-volume ed. Charles Scribner's Sons, 1968.