Perera, R.R.S.; Rupasinghe, L.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)
Aththanayaka, A.M.L.; Rupasingha, L.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)