1. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance; Institute of the Ruhr-Universität Bochum (IPA); Bochum Germany
2. Department of Dermatology and Allergology; University Medical Center (UKGM); Justus-Liebig University Giessen; Germany
3. Malteser Lung and Allergy Centre Bonn; Bonn Germany
4. Medical Practice for Pediatrics; Bretten Germany
5. Department of Pulmonary Diseases; Fachkrankenhaus Coswig; Centre for Pulmonary Diseases and Thoracic Surgery; Coswig Germany
6. Berufsgenossenschaftliche Klinik für Berufskrankheiten Falkenstein; Falkenstein Germany
7. Asthma Allergy Centre; Leverkusen Germany
8. Johanniter-Hospital; Treuenbrietzen Germany
9. Department of Dermatology and Allergology; University Hospital RWTH Aachen; Aachen Germany
10. Allergology; Medical Practice for Respiratory Medicine; Köln Germany
11. Pediatric Pneumology/Allergy; Children's Hospital Princess Margaret; Darmstadt Germany
12. Pulmonary and Allergy Practice; Lahr Germany
13. Department of Occupational Diseases; Nofer Institute of Occupational Medicine; Lodz Poland