Thompson, F.G.
Longman Scientific & Technical, 1992
Buku Teks
Thompson, F.G.
Longmans, Green and Co, Ltd., 1968
Buku Teks
Lewis, Maurice
Stanley Thornes Publishers, 1993
Buku Teks
Francis, Thomas George
Longman, 1988
Buku Teks
Francis, Thomas George
ELBS, 1992
Buku Teks