Chan, J.N., Chingcuanco, L.V., Jallorina, M. and Lagrosas, N.D. 2007. Case study of the correlation of black carbon content and pixel values of Teflon filters. Proceedings of the Samahang Pisika ng Pilipinas, 25(1), SPP-2007-2C-04. URL: https://proceedings.spp-online.org/article/view/SPP-2007-2C-04.