Antieau, Chester James, author
Dennis & Co., 1960
Buku Teks
Hamilton, Alexander, author
Tudor Publishing, 1937
Buku Teks
Beard, Charles A., author
Macmillan, 1957
Buku Teks
Corwin, Edward S., author
U.S. Government Printing Office, 1953
Buku Teks
Norton, Thomas James
America`s Future, Inc., 1946
Buku Teks