Fonseka, A.A.S.; Withanage, S.P.; Attanayaka, D.P.T.S.G.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Perera, J.K.C.G.K.; Ramanayake, S.M.S.D.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)