Galston, William A., author
Cambridge University Press, 2005
Buku Teks
Muñiz-Fraticelli, Victor Manuel, author
Oxford University Press, 2014
Buku Teks
Jaklic, Klemen, author
Oxford University Press, 2014
Buku Teks
Grayson, George W., author
Thomson, 2004
Buku Teks
Friedrich Ebert Stiftung, 2005
Buku Teks