Agranoff, Robert, author
Georgetown University Pres, 2012
Buku Teks
Smith, Kevin, author
Westview Press, Boston, Massachusetts : Credo Reference, 2013
Buku Teks
Siepmann, Otto, author
Macmillan, 1908
Buku Teks
Flynn, Norman, author
Harvester, 1990
Buku Teks
Van Wart, Montgomery, author
Garland, 1998
Buku Teks