Estoque, M.A. and Balmori, R.T.F. 2002. Predictability of droughts and floods due to El Niño and La Niña episodes. Proceedings of the Samahang Pisika ng Pilipinas, 20(1), SPP-2002-1A-02. URL: https://proceedings.spp-online.org/article/view/SPP-2002-1A-02.