Grinnell, Richard M., author
F.E. Peacock Publishers, 2001
Buku Teks
Edwards, Anne, author
Longman, 1996
Buku Teks
edited by Jan Fook
Allen & Unwin, 1996
Buku Teks
Routledge, 2015
Buku Teks
Grinnell, Richard M., author
Oxford University Press, 2018
Buku Teks