Brown, Penelope
Cambridge University Press , 1987
Buku Teks
Sandler, Wendy
Cambridge University Press, 2006
Buku Teks
Bloomfield, Leonard
Holt, Rinehart and Winston, 1961
Buku Teks
Cambridge University Press, 2006
eBooks
Beard, Adrian
Routledge, 2004
Buku Teks