Dawson, Paul, author
Routledge, 2005
Buku Teks
Whitten, Mary E., author
Harcourt, 1966
Buku Teks
edited by Davis S. Miall
Clarendon Press, 1990
Buku Teks
Joyce, Helen de Silva, author
Phoenix Education, 2000
Buku Teks
Mills, Paul, author
Routledge, 2006
Buku Teks