Dickerson, Reed, author
Little, Brown and Company, 1975
Buku Teks
Williams, Robin W., author
Alfred A. Knopf, 1963
Buku Teks
Williams, Robin M., author
Alfred A. Knopf, 1966
Buku Teks
Princeton University Press, 1944
Buku Teks
Atkins, Ruth, author
John Wiley & Sons, 1980
Buku Teks