Villarin, J.T. and Narisma, G.T. 1999. Estimating the gravity of particulate pollution due to transport in Metro Manila. Proceedings of the Samahang Pisika ng Pilipinas, 17(1), SPP-1999-SG-10. URL: https://proceedings.spp-online.org/article/view/SPP-1999-SG-10.