Porter, Charles O. (Charles Orlando), 1919-2006
Macmillan, 1961
Buku Teks
Cambridge University Press, 1997
eBooks
Busey, James L.
Random House, 1968
Buku Teks
Ward, John
Routledge , 1997
Buku Teks
edited by Alex E. Fernandez Jilberto and Andre Mommen
Routledge, 1996
Buku Teks