Oliver, Douglas L., author
Harvard University Press, 1958.
Buku Teks
McCune, George M., author
Harvard University Press, 1950
Buku Teks
Craven, John P., author
Westview Press, 1982
Buku Teks
Melbourne University, 1941
Buku Teks
Tow, William T., author
Cambridge University Press, 2001
Buku Teks