Lafosse, Michael G., author
Quarry Books, 1998
Buku Referensi
Ang, Tom, author
Mitchell Beazley, 1999
Buku Referensi
Davenport, Dawn, author
Broadway Books, 2006
Buku Teks
Peacock, Janet L., auhtor
Oxford University Press, 2007
Buku Teks
Kellett, Mary, author
Paul Chapman Publishing, 2005
Buku Teks