1. Department of Pediatrics, Wilhelmina Children's Hospital, Utrecht, The Netherlands
2. Department of Pediatrics, Maxima Medical Center, Veldhoven, The Netherlands
3. Julius Center for Health Sciences and Primary Care, Utrecht, The Netherlands
4. University Medical Center, Utrecht, The Netherlands
5. Division of Pediatric Urology, University Essen-Duisburg, Essen, Germany
6. Maxima Medical Center, Veldhoven, The Netherlands
7. Department of Pediatrics, Gasthuisberg University Hospital, Leuven, Belgium