Maltzoff, Nicholas
Ellinois Passport Book, 1994
Buku Teks
Murray, John D. (John Damian)
Routledge, 2001
Buku Teks
Timberlake, Alan
Cambridge University Press, 2004
Buku Teks
Lusin, Natala
Baron's Education, 1992
Buku Referensi
Wade, Terence
New York : Oxford University Press, 2002
Buku Referensi