Dallin, David
Hollis & Carter, 1949
Buku Teks
Fainsod, Merle, author
Harvard University Press, 1956
Buku Teks
Kennan, George F., 1904-, author
An Atlantic Monthly Press Book, 1961
Buku Teks
Carr, Edward Hallet, author
Macmillan, 1954
Buku Teks
Daniels, Robert V
Westview Press, 1988
Buku Teks