Paber, Justin Elfred Lan B., Michael Salvador D. Cabato, Romeo L. Villarta, and Josefino G. Hernandez. 2008. “Radiographic Analysis of the Ethmoid Roof Based on KEROS Classification Among Filipinos”. Philippine Journal of Otolaryngology Head and Neck Surgery 23 (1):15-19. https://doi.org/10.32412/pjohns.v23i1.763.