Paber, J.E.L.B., Cabato, M.S.D., Villarta, R.L. and Hernandez, J.G. 2008. Radiographic Analysis of the Ethmoid Roof based on KEROS Classification among Filipinos. Philippine Journal of Otolaryngology Head and Neck Surgery. 23, 1 (Jun. 2008), 15–19. DOI:https://doi.org/10.32412/pjohns.v23i1.763.