Hartley, Paul, author
Companion Website, 2006
Buku Teks
Coggle, Paul, author
Teach Youeself Books, 1991
Buku Teks
Wilkes, Angela
Chicago: A Division of NTC Pub., 1987,
Buku Referensi
Burke, Claire
New York Routledge, 1999
Buku Teks
Coggle, Paul, author
Kesaint Blanc, 2010
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