Rathnayake, R.M.C.P.; Perera, W.G.S.; Dassanayake, E.M.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)
Rangana, S.H.C.S.; Basnayake, B.M.V.S.; Perera, W.G.S.; Dassanayake, E.M.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)