Cook, Arthur N., author
Littlefield Adams, 1969
Buku Teks
Rooney, D.D., author
George G. Harrap, 1967
Buku Teks
July, Robert W
Charles Scribner's, 1970
Buku Teks
Bohannan, Paul, author
The National History Press, 1964
Buku Teks
Italiaander, Rolf
Prentice-Hall, 1961
Buku Teks