1. UK Cochrane Centre; Oxford UK
2. Faculty of Medicine, Khon Kaen University; Department of Otorhinolaryngology; Khon Kaen Thailand
3. National Institute for Health and Care Excellence; Level 1A, City Tower Piccadilly Plaza Manchester UK M1 4BT
4. Chulalongkorn University; Department of Otolaryngology, Faculty of Medicine; Bangkok Thailand
5. Norwich Medical School, University of East Anglia; Department of Medicine; Norwich UK NR4 7TJ
6. Guy's Hospital; ENT Department; Gerat Maze Pond London UK SE1 9RT
7. Cochrane UK; Summertown Pavilion 18 - 24 Middle Way Oxford UK OX2 7LG