Cullingworth, J.B., author
Allen & Unwin, 1979
Buku Teks
Clark, Anna, author
Rivers Oram, 1995
Buku Teks
edited by Bob Franklin
Routledge, 1991
Buku Teks
Davies, J.B. Meredith, author
Baillere Tindall, 1975
Buku Teks
Carolyn Jackson, Claire Thurgate
McGraw-Hill, 2011
Buku Teks