Weerakoon, W.M.C.S.; Gajanayake, K.G.M.C.P.B.; Jayasinghe-Mudalige, U.K.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2006)
Senanayake, S.M.S.D.; Karunarathne, K.H.M.I.; Wickramasinghe, H.K.J.P.(Faculty of Agriculture and Plantation Management,Wayamba University of Sri Lanka, Makandura, 2016)