“Anatomical Variations of the Frontal Sinus Drainage Pathway According to the IFAC Classification: Frequency and Interobserver Agreement in a Paraguayan Population”. European Journal of Health Research 12 (March 24, 2026): 1–17. Accessed June 26, 2026. https://revistas.uautonoma.cl/index.php/ejhr/article/view/3614.