1. Hospital for Lung Disease “St. Sofia”, Bulgaria
2. The Children’s Hospital at Westmead, Australia; University of Sydney, Australia
3. State University of New York, USA
4. Royal London Hospital, United Kingdom; Barts and the London School of Medicine and Dentistry, United Kingdom
5. Istituti Clinici Scientifici Maugeri, Italia
6. University College of London, United Kingdom