R.S. Ramakrishna, R.E. Rajaseelan, J.M.T.B. Karunaratne, M. Balasubramaniam, R.R. Brooks, D.E. Ryan and J. Holzbecher 1985. A geochemical reconnaissance survey of Sri Lanka using panned mineral concentrates of stream sediments. Netherlands Journal of Geosciences. (Jan. 1985), 237-244.