Hurst, James Willard
Little, Brown, 1950
Buku Teks
Wright, Benjamin F.
Phoenik Books, 1967
Buku Teks
Dam, Kenneth W.
The Brooking Institution, 2006
Buku Teks
Garvey, George E.
Greenwood Press, 1990
Buku Teks
Pound, Roscoe
University of Pitsburgh Press, 1942
Buku Teks