consultant ed. Tanya A. McFerran
Oxford University Press, 1996
Buku Referensi
Peter Salim, author
Modern English Press, 1991
Buku Referensi
Churchill Livingstone, 1996
Buku Referensi
edited by Tamara Myers
Mosby Elsevier, 2006
Buku Teks
Park, Chris, author
Oxford University Press, 2008
Buku Referensi