APA (7th ed.) Citation

Sumner, W. G., & Keller, A. G. (1914). The challenge of facts, and other essays. Yale University Press.

Chicago Style (17th ed.) Citation

Sumner, William Graham, and Albert Galloway Keller. The Challenge of Facts, and Other Essays. New Haven: Yale University Press, 1914.

MLA (9th ed.) Citation

Sumner, William Graham, and Albert Galloway Keller. The Challenge of Facts, and Other Essays. Yale University Press, 1914.