1. University childrens hospital CHU Sainte Justine, 3175, Chemin de la Côte-Sainte-Catherine, Montréal H3T 1C5, Québec, Canada, Gastroentérologie, Montréal, Canada
2. Cantonal Hospital Lucerne. Pediatric departement, Lucerne, Switzerland
3. Cantonal Hospital St. Gallen, Surgery, St.Gallen, Switzerland
4. Cantonal Hospital Lucerne, Pediatric Haematology and Oncology, Lucerne, Switzerland