Citazione APA

Sumner, W. G., & Keller, A. G. (1914). The challenge of facts: And other essays. Yale University Press; [etc., etc.].

Stile di citazione Chicago

Sumner, William Graham, e Albert Galloway Keller. The Challenge of Facts: And Other Essays. New Haven: Yale University Press; [etc., etc.], 1914.

Citazione MLA

Sumner, William Graham, e Albert Galloway Keller. The Challenge of Facts: And Other Essays. Yale University Press; [etc., etc.], 1914.