APA (7th ed.) Zitazioa
Siemers, D. J. (2009). Presidents and political thought. University of Missouri Press.
Chicago Style (17th ed.) Zitazioa
Siemers, David J. Presidents and Political Thought. Columbia: University of Missouri Press, 2009.
MLA (9th ed.) Zitazioa
Siemers, David J. Presidents and Political Thought. University of Missouri Press, 2009.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.