Jayamaha, D.J.M.N.; Samarajeewa, P.K.; Attanayaka, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)
Kumara, U.W.A.; Samarajeewa, P.K.; Attanayaka, D.P.T.S.G.(Faculty of Agriculture and Plantation Management, Wayamba University of Sri Lanka, Makandura, 2005)