1. Common Cold Centre, Cardiff School of Biosciences, Cardiff University, United Kingdom
2. Nycomed, Roskilde, Denmark
3. Alviva AB, Brumma, Stockholm, Sweden
4. Occupational Health Department, Clinic Mehiläinen, Turku, Finland
5. Ear-Nose-Throat Department, Køge University Hospital, Copenhagen, Denmark
6. Ear, Nose, and Throat Department, Karolinska University Hospital/Huddinge, Stockholm, Sweden