1. Department of Health Services Research, Carl von Ossietzky University, Oldenburg, Germany
2. Department of Orthopedics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
3. School of Medicine and Health Sciences, Carl von Ossietzky University, Oldenburg, Germany
4. Preston Smith Library, Texas Tech University Health Sciences Center, Lobbock, Texas, USA
5. Chair of Medical Sociology, Institute of Medical Sociology, Health Services Research and Rehabilitation Science (IMVR) Faculty of Medicine, University of Cologne, Oldenburg, Germany
6. University Hospital of Orthopedics and Trauma Surgery Pius-Hospital, Medical Campus University of Oldenburg, Oldenburg, Germany