Neranjika, V.P.M.; Abeynayake, N.R.; Fernando, M.T.N.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Subasinghe, S.A.M.S.; Abeynayake, N.R.; Shyamale, H.W.; Wellala, N.N.K.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2013)