Grazia, A. d. (1949). Roberto Michels' first lectures in political sociology. Harper Torchbooks.
Chicago-viite (17. p.)Grazia, Alfred de. Roberto Michels' First Lectures in Political Sociology. New York: Harper Torchbooks, 1949.
MLA-viite (9. p.)Grazia, Alfred de. Roberto Michels' First Lectures in Political Sociology. Harper Torchbooks, 1949.
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