1. Effects of vegetal cover on soil erosion on an Alfisol;Aina,1979
2. Nutrient removal by crops growing in the dry zone of Sri Lanka;Amarasiri;Trop. Agric.,1975
3. Cassava Program Annual Report for 1979;Anonymous,1980
4. Cassava Program Annual Report for 1982 and 1983;Anonymous,1984
5. Annual Report for 1986;Anonymous,1987