1. Department of Otorhinolaryngology–Head and Neck Surgery, College of Medicine, Konkuk University, Seoul, Korea
2. Head and Neck Institute, Cleveland Clinic Foundation, Cleveland, Ohio
3. Department of Otorhinolaryngology–Head and Neck Surgery, College of Medicine, Korea University, Seoul, Korea
4. Department of Otorhinolaryngology, College of Medicine, Yonsei University, Seoul, Korea
5. Airway Mucus Institute, Seoul, Korea