Harshana, W.H.I.; Nugawela, R.C.W.M.R.A.; Attanayake, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)
Nirosha, S.F.; De Silva, S.N.T.; Attanayake, D.P.S.T.G.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)