De Guzman, Isaac Cesar S. “Tracheal Diameter Estimates Using Age-Related Formula Versus Radiographic Findings: Which Approximates the Actual Tracheostomy Tube in Pediatric Patients?”. Philippine Journal of Otolaryngology Head and Neck Surgery 33, no. 2 (November 13, 2018): 32–36. Accessed April 20, 2024. https://pjohns.pso-hns.org/index.php/pjohns/article/view/271.