Murray, Rowena
Open University Press, 2002
Buku Teks
Evans, David, author
Melbourne University Press, 2002
Buku Teks
Day, Robert A., author
ISI Press , 1979
Buku Teks
Berry, Ralph, author
London : ROUTLEDGE, 1994,
Buku Referensi
Berry, Ralph, author
Routledge, 1994
Buku Teks