Sirirattanapan, Jarinratn, Suprapol Chantapan, and Suriya Pongsawat. 2015. “A Rare Upper Airway Obstruction by Large Hemorrhagic Vocal Polyps”. Journal of Medicine and Health Sciences 22 (1):93-98. https://he01.tci-thaijo.org/index.php/jmhs/article/view/58643.