Catton, Bruce, author
Dell Publishing, 1956
Buku Teks
Ketchum, Richard M., author
American Heritage Publishing, 1960
Buku Teks
Catton, Bruce, author
Dell Publishing, 1960
Buku Teks
W.H. Freeman and Company, 1993
Buku Teks
Kuykendall, Ralph S., author
Prentice-Hall, 1961
Buku Teks