McGraw-hill book , 1950
Buku Teks
Lovejoy, Laurence C., author
Aleander Hamilton Institute, 1962
Buku Teks
Roethlisberger, F.J.
Harvard University Press, 1956
Buku Teks
Yoder, Dale, author
McGraw-Hill, 1958
Buku Teks
Yoder, Dale, author
Prentice-Hall, 1962
Buku Teks