Kumarasinghe, W.M.; Perera, S.A.C.N.; Gunasekara, T.M.C.P.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)
Wijeratne, K.D.B.M.; Adikaram, N.K.B.; Yakandawala, D.M.D.; Yakandawala, K.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)