Teggart, Frederick J.
University of California Press, 1939
Buku Teks
Samuels, Richard J.
Cornell University Press, 1990
Buku Teks
Dolan, Josephine A., author
WB Saunder comp , 1983
Buku Teks
Wade, Nicholas J., author
Springer, 2005
Buku Teks
Kiching, Covin
Methuen, 1982
Buku Teks