Passmore, John, author
Gerald Duckworth, 1957
Buku Teks
Passmore, John, author
Penguin Books, 1972
Buku Teks
Williams, Melanie, author
Cavendish Publishing Limited, 2002
Buku Teks
Penniman, T.K.
Duckworth, 1935
Buku Teks
Smellie, Kingsley Bryce, 1897-1987
Gerald Duckworth & Co,LTD, 1950
Buku Teks