1. Children's Memorial Health Institute, Warsaw, Poland.
2. Dr. von Hauner Children's Hospital, University of Munich Medical Centre, Munich, Germany.
3. Centre Hospitalier Chrétien St. Vincent, Liège-Rocourt, Belgium.
4. University Children's Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium.
5. Universitat Rovira i Virgili, IISPV, Reus, Spain.
6. San Paolo Hospital University of Milan, Milan, Italy.