1. Department of Otorhinolaryngology, Faculty of Medicine, Universiti Kebangsaan Malaysia
2. Allergy Unit, Hospital Canselor Tuanku Mukhriz, Jalan Yaacob Latiff, Bandar Tun Razak, Kuala Lumpur, Malaysia
3. Faculty of Medicine Siriraj Hospital, Mahidol University
4. Mahidol University Faculty of Medicine Siriraj Hospital, Bangkok, Thailand