1. Department of Business Administration and Health Care Management, Faculty of Management, Economics and Social Sciences University of Cologne Cologne Germany
2. Department of Pediatrics, University Hospital, Faculty of Medicine University of Cologne Cologne Germany
3. Department of Pediatric Neurology, University Children's Hospital (UKGM), Faculty of Medicine Justus Liebig University of Giessen Cologne Germany
4. Institute of Medical Sociology, Health Services Research and Rehabilitation Science, Faculty of Human Sciences and Faculty of Medicine University of Cologne Cologne Germany