1. Institute of Medical Statistics, Informatics and Epidemiology, University Hospital of Cologne, 50931 Cologne, Germany.
2. Department of Ear, Nose, and Throat, United Christian Hospital and Department of Otorhinolaryngology, Head and Neck Surgery, Chinese University of Hong Kong, Hong Kong, China.
3. University of the Philippines College of Medicine and Philippine General Hospital, 1000 Manila, Philippines.
4. The KL Skin Centre, Pantai Hospital, 59100 Kuala Lumpur, Malaysia.
5. Ascent Ear Nose Throat Specialist Group, Mount Elizabeth Medical Centre, Singapore 228510, Singapore.
6. Hospital Raja Permaisuri Bainun (Ipoh General Hospital), 30990 Ipoh, Malaysia.
7. Department of Otorhinolaryngology, Prince Court Medical Centre, 50450 Kuala Lumpur, Malaysia.
8. Department of Otorhinolaryngology-Head & Neck Surgery, University of Santo Tomas, 1008 Manila, Philippines.