Ong, John, 		Aguda, Nancy, 		Jaraula, Caroline, 		Mateo, Zenon, 		Pascua, Chelo, AND 		Foronda, Joseph.
" Tidal Effects on Groundwater in a Very Small Tropical Island: A Study on the Groundwater Resources of Pag-asa Island, Kalayaan Island Group" <em>Science Diliman: A Journal of Pure and Applied Sciences</em> [Online], Volume 12 Number 2 (7 September 2007)