Lucas, J. R.Perera, H.Y.R.Wijayatunga, P. D. C.Wijeratna, D. C.Siyambalapitiya, T.Jayasekara, T.A.K2014-10-302014-10-301995SLEMA Journal, 6(1):p.1-10https://dl.nsf.gov.lk/handle/1/11596Article