Rathnasekara, G.N.C.; Gajanayake, K.G.M.C.P.B.; Abeyagunawardene, C.D.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Razmy, M.A.A.; Athauda, A.M.T.P.; Arachchige, T.D.P.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)