1. Department of Respiratory Medicine; Academic Medical Centre; Amsterdam
2. Department of Respiratory Medicine; Medical Centre Leeuwarden; Leeuwarden
3. Department of Respiratory Medicine; Tergooi Hospital; Blaricum
4. Department of Respiratory Medicine; Slotervaart Hospital; Amsterdam
5. Department of Respiratory Medicine; Spaarne Hospital; Hoofddorp
6. Departments of Respiratory Medicine and Experimental Immunology; Academic Medical Centre; Amsterdam
7. Department of Epidemiology and Bioinformatics; Academic Medical Centre; Amsterdam; Netherlands