Kumari, R.M.P.D.; Gajanayake, K.G.M.C.P.B.; Chandrasekara, G.A.P.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Rathnayake, B.M.D.I.; Athauda, A.M.T.P.; Abeynayake, N.R.; Patale, M.A.B.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2013)