Harrison, Brigid C., author
Thomson, 2008
Buku Teks
Junker, Buford H., author
University of Chicago Press, 1960
Buku Teks
Delong, Kenric, author
Brooks/Cole, 1987
Buku Teks
Blackman, Sheldon, author
John Wiley & Sons, 1971
Buku Teks
May, John D.
Duxbury Press, 1972
Buku Teks