Hunter, Robert E., author
Praeger, 1982
Buku Teks
Rourke, Francis E., author
John Hopkins University Press, 1972
Buku Teks
Divine, Robert A., author
New Viewpoints, 1974
Buku Teks
Lovel, John P
Macmillan, 1985
Buku Teks
Rosati, Jerel A., 1953-, author
Wadsworth, 2007
Buku Teks