Mason, Alpheus Thomas,1899-1989
Cornel University Press, 1955
Buku Teks
Steinby, Torsten
Government, 1971
Buku Teks
Grande, Sandy, 1964-
Rowman and Littlefield, 2015
Buku Teks
Fowler, Robert Booth
University Press of Kansas, 1991
Buku Teks
Gettell, Raymond G.
Appleton-Century-Crofts, 1928
Buku Teks