Whitten, Mary E.
Harcourt, 1966
Buku Teks
edited by Davis S. Miall
Clarendon Press, 1990
Buku Teks
Joyce, Helen de Silva
Phoenix Education, 2000
Buku Teks
Mills, Paul
Routledge, 2006
Buku Teks
Routledge in association with the Open University, 2006
Buku Teks