Clarke, E. L. (1929). The art of straight thinking: A primer of scientific method for social inquiry. Appleton-Century.
Chicago-viite (17. p.)Clarke, Edwin Leavitt. The Art of Straight Thinking: A Primer of Scientific Method for Social Inquiry. New York: Appleton-Century, 1929.
MLA-viite (9. p.)Clarke, Edwin Leavitt. The Art of Straight Thinking: A Primer of Scientific Method for Social Inquiry. Appleton-Century, 1929.
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