McCormick, James M., author
Thomson, 2005
Buku Teks
Herrick, Christopher, author
Longman, 2003
Buku Teks
Brown, William Adams, author
Brookongs Institutons, 1954
Buku Teks
Langdon, Robert M., author
Littlefield Adams, 1961
Buku Teks
Bruce Michael Bagley, Roberto Alvarez, and Katherine J. Hagedorn, editors
Westview Press, 1985
Buku Teks