Dharmaratne, P.P.; Gajanayake, B.; Karunarathna, K.M.H.I.; Priyadarshane, L.B.M.D.L.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)
Weerasekera, W.M.P.M.; Abeynayake, N.R.; Attanayake, A.M.C.M.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2013)