Carney, Terry
Oxford University Press Australia, 1991
Buku Teks
edited by Thomas and Dorothy Wilson
Longman, 1991
Buku Teks
Hindess, Barry, author
Tavistock , 1987
Buku Teks
George, Victor
Routledge & Kegan Paul, 1985
Buku Teks
Spicker, Paul
Prentice-Hall, 1995
Buku Teks