Hall, Rodney
University of Queensland, 1972
Buku Teks
The University of Michigan, 1998
Buku Teks
Roberts, Denys Kilham
Penguin Books , 1945
Buku Teks
Palgrave, Francis T.
Macmillan, 1922
Buku Teks
Nims, John Frederick
Harper & Row Pub., 1981
Buku Teks