Flavin, Christopher, author
Worldwatch Institute , 1986
Buku Teks
Third World Foundation for Social and Economics Studies, 1985
Buku Teks
Macmillan, 1971
Buku Teks
Williams, Marc
Harvester Wheatsheaf , 1994
Buku Teks
Bugajski, Janusz, author
Westview Press, 1991
Buku Teks