1. Department of Paediatric Surgery, Children's Hospital in Lund, Skane University Hospital Lund, Lund, Sweden
2. Department of Paediatric Surgery, Paediatric Research Centre, Children's Hospital, Helsinki University Hospital, Helsinki, Finland
3. Department of Paediatric Surgery, Queen Silvia's Children's Hospital, Sahlgrenska University Hospital Gothenburg, Gothenburg, Sweden
4. Department of Paediatric Surgery, Uppsala University Children's Hospital, Uppsala, Sweden
5. Department of Paediatric Surgery, Oslo University Hospital, Oslo, Norway
6. Division of Paediatric Surgery, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
7. Department of Paediatric Surgery, Odense University Hospital, Research Unit Surgery, University of Southern Denmark, Odense
8. Department of Paediatric Surgery, Rikshospitalet Copenhagen, Copenhagen, Denmark