Punyasena, M.A.; Amarasekara, C.D.; Jayakody, J.R.P.; Perera, P.A.A.(Annual Research Symposium, Faculty of Graduate Studies, University of Kelaniya, 2001)
Perera, P.A.A.; Amarasekara, C.D.; Jayakody, J.R.P.; Punyasena, M.A.(Annual Research Symposium, Faculty of Graduate Studies, University of Kelaniya, 2002)