1. Visceral Surgery; Hirslanden Klinik St. Anna; Luzern Switzerland
2. Department of Visceral and Thoracic Surgery; Cantonal Hospital of Winterthur; Winterthur Switzerland
3. Department for Visceral Surgery and Medicine; Bern University Hospital, University of Bern; Bern Switzerland
4. Department of Mathematics; Cantonal School of Wil; St. Gallen Switzerland
5. Department of Cardiology, University Heart Centre; University Hospital Zurich; Zurich Switzerland
6. Department of Pediatric Surgery; University of Leipzig; Leipzig Germany
7. Cochrane Switzerland, Center for Primary Care and Public Health (Unisanté); University of Lausanne; Lausanne Switzerland
8. Children's Hospital Colorado and University of Colorado School of Medicine; Denver CO USA
9. Department of Pediatric Surgery; Children's University Hospital; Basel Switzerland