APA (7th ed.) Citation

Spengler, O., Werner, H., Helps, A., & Atkinson, C. F. (1991). The decline of the West. Oxford University press.

Chicago Style (17th ed.) Citation

Spengler, Oswald, Helmut Werner, Arthur Helps, and Charles Francis Atkinson. The Decline of the West. New York ; Oxford: Oxford University press, 1991.

MLA (8th ed.) Citation

Spengler, Oswald, et al. The Decline of the West. Oxford University press, 1991.