Pilcher, Rosamunde
Coronet Books, 1990
Buku Teks
Nation, I.S.P., author
Cambridge University Press, 2013
Buku Teks
Pile, John, author
Watson-Guptil, 1976
Buku Referensi
Bahamon, Alejandro
New York : Page One, 2004,
Buku Referensi
Bahamon, Alejandro, author
Page One Pub, 2004
Buku Referensi