Wijepala, S.A.T.P.; Lakmali, W.A.S.; Alawathugoda, R.M.D.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)
Muhsin, A.M.I.; Fernando, M.T.N.; Athauda, A.M.T.P.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)