Milton, Geroge Fort
Little, Brown and Company, 1944
Buku Teks
Smith, John Malcolm
Public affairs Press, 1960
Buku Teks
Fisher, Louis, author
Oxford University Press, 2014
Buku Teks
Hunter, Robert E., author
Praeger, 1982
Buku Teks
Cater, Douglass
Vintage Books, 1964
Buku Teks