Niran, H.M.L.; Rodrigo, V.H.L.; Nayanakantha, N.M.C.N.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Dissanayake, K.M.R.; Rodrigo, V.H.L.; Balasooriya, B.M.D.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)