Bandara, B.W.M.; Gajanayake, K.G.M.C.P.B.; Jayasinghe-Mudalige, U.K.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2006)
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)