Sturrock, Ford, author
Pitman, 1982
Buku Teks
edited by P.J.S. Olney, G.M. Mace and A.T.C. Feistner
Chapman & Hall, 1994
Buku Teks
The Agricultural Development Council, 1972
Buku Teks
Orwell, George, 1903-1950, author
Everyman's Library, 1993
Buku Teks
Brown, Maxwell L., author
John Hopkins University Press, 1979
Buku Teks