Wilmshurst, John, author
Redwood Press, 1985
Buku Teks
Fletcher, Alan D., author
Grid Publishing, 1983
Buku Teks
Fletcher, Alan D., author
Wadsworth , 1987
Buku Teks
Hotchkiss, George Burton, author
Alexander Hamilton Institute , 1961
Buku Teks
Wells, William D., author
Prentice-Hall, 2000
Buku Teks