Udadeniya, U.V.P.N.; Ranasinghe, C.S.; Abeysinghe, D.C.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)
Balasooriya, C.G.; Karunagoda, K.S.; Athauda, A.M.T.P.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)