Curry, Steve, author
St. Martin's Press , 1993
Buku Teks
United Nations , 1987
Buku Teks
edited by Arnold Pacey for Oxfam and the Ross Institute of Tropical Hygiene
John Wiley & Sons, 1978
Buku Teks
Clarke, John I., author
Pergamon Press, 1979
Buku Teks
East-West Center Press, 1967
Buku Teks