Sajeewani, M.A.I.; Withanage, S.P.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)
Edirisinghe, E.A.D.D.; Withanage, S.P.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)