Cohen, Andrew Jason
Polity, 2014
Buku Teks
Welch, Joseph N.
Houghton Miffiln, 1956
Buku Teks
Amery, L.S.
Oxford University Press, 1953
Buku Teks
Corwin, Edward S.
William Sloane, 1949
Buku Teks
Cox, Archibald, 1912-2004
Houghton Mifflin, 1987
Buku Teks