Goldstein, Herbert, author
Addison-Wesley, 1962
Buku Teks
Matzner, Richard A., author
Prentice-Hall, 1991
Buku Teks
Iowa : The Torch Press
Majalah, Jurnal, Buletin
The University of Chicago Press, 1978
Majalah, Jurnal, Buletin
Bowra, C. M., author
Time-Life Books, 1965
Buku Teks