Thompson, Kenneth W., author
Princeton University Press, 1960
Buku Teks
Perkins, Dexter
Harvard University Press, 1954
Buku Teks
Callahan, David
Harper Collins , 1994
Buku Teks
Henry Holt and Company , 1955
Buku Teks
Nathan, James A
Little, Brown, 1983
Buku Teks