Byrne, David, author
Routledge, 1998
Buku Teks
Brown, Gary D., author
McGraw-Hill, [Date of publication not identified]
Buku Teks
Standford University Press, 1996
Buku Teks
Pratt Vernon
Methuen Press, 1978
Buku Teks
Junker, Buford H., author
University of Chicago Press, 1960
Buku Teks