1. Department of Pediatric Surgery, Centro Hospitalar Universitário do Porto EPE Centro Materno-Infantil do Norte Dr Albino Aroso, Porto, Portugal
2. Department of Pediatric Surgery, Centro Hospitalar Universitário do Porto EPE, Porto, Portugal
3. Department of Pediatric Surgery, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milano, Italy
4. Department of Pediatric Surgery, Schneider Children's Medical Center of Israel, Petah Tikva, Israel
5. Department of Pediatric Surgery, Vall d'Hebron University Hospital, Barcelona, Catalunya, Spain
6. Department of Pediatric Surgery, Emma Childrens' Hospital UMC, Amsterdam, Noord-Holland, The Netherlands
7. Department of Pediatric Urology, Hospital Universitario La Paz, Madrid, Spain
8. Department of Pediatric Surgery, Hospital Universitário La Paz, Madrid, Spain