Ketchum, Richard M.
American Heritage Publishing, 1960
Buku Teks SO
Catton, Bruce
Dell Publishing, 1960
Buku Teks SO
W.H. Freeman, 1993
Buku Teks SO
Alic, Margaret
Women's Press, 1986
Buku Teks SO
Kuykendall, Ralph S.
Prentice-Hall, 1961
Buku Teks SO