Yarmolinsky, Adam.
Twentieth Century Fund., 1971
Buku Teks
The University of Chicago Press, 1948
Buku Teks
O`Hamlon, Michael E.
Princeton University Press, 2009.
Buku Teks
Hitch, Charles J., author
University of California Press, 1965
Buku Teks
Goulding, Phil G., author
Harper & Row, 1970
Buku Teks