Oblefias, W.R., Soriano, M.N. and Saloma, C.A. 2007. Two dimensional concentration maps through spectral estimation and spectral unmixing. Proceedings of the Samahang Pisika ng Pilipinas, 25(1), SPP-2007-3C-03. URL: https://proceedings.spp-online.org/article/view/SPP-2007-3C-03.