Pfiffner, J. P. (2004). The character factor: How we judge America's presidents. Texas A & M University Press.
Lua i Stíl Chicago (17ú heag.)Pfiffner, James P. The Character Factor: How We Judge America's Presidents. College Station, Tex.: Texas A & M University Press, 2004.
Lua MLA (9ú heag.)Pfiffner, James P. The Character Factor: How We Judge America's Presidents. Texas A & M University Press, 2004.
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