Ur, Penny, author
Cambridge University Press, 1988
Buku Teks
Dunn, John, 1940-, author
Routledge, 2009
Buku Referensi
Dunn, John A., 1949-, author
Routledge, 2009
Buku Teks
Rorden, Judith Waring, author
W.B. Saunders Company, 1987
Buku Teks
Ross, Claudia, author
Routledge, 2006
Buku Referensi