Ladd, G. T. (1914). What can I know?: An inquiry into truth, its nature, the means of its attainment, and its relations to the practical life. Longmans, Green.
Chicago-referens (17:e uppl.)Ladd, George Trumbull. What Can I Know?: An Inquiry into Truth, Its Nature, the Means of Its Attainment, and Its Relations to the Practical Life. New York: Longmans, Green, 1914.
MLA-referens (8:e uppl.)Ladd, George Trumbull. What Can I Know?: An Inquiry into Truth, Its Nature, the Means of Its Attainment, and Its Relations to the Practical Life. Longmans, Green, 1914.
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