Denham, Paul
Stanley Thornes, 1987
Buku Teks
Rose, Richard, 1933-, author
Scott, Foreman, 1989
Buku Teks
Jones, Bill, author
Manchester University Press, 1993
Buku Teks
Jones, Bill, author
Manchester University Press, 1991
Buku Teks
Madgwick, P.J., author
Stanley Thornes, 1992
Buku Teks