Barber, J. D. (1964). Political leadership in american government. Little, Brown and Company.
Lua i Stíl Chicago (17ú heag.)Barber, James David. Political Leadership in American Government. Boston: Little, Brown and Company, 1964.
Lua MLA (9ú heag.)Barber, James David. Political Leadership in American Government. Little, Brown and Company, 1964.
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