White, James L.
Washington Square Press, 1966
Buku Teks
Smith, Thomas C.
Standford University Press, 1959
Buku Teks
Smith, Thomas C.
Standford University Press, 1965
Buku Teks
Watson, H.B.
Oxford University Press , 1949
Buku Teks
Butterfield, Herbert
The Free Press , 1957
Buku Teks