1. Department of Urology, Sindelfingen-Boeblingen Medical Center, University of Tübingen, Tübingen, Germany
2. Department of Traumatology and Orthopaedics, Vivantes Klinikum Spandau, Berlin, Germany
3. Department of Urology, Zeisigwald Clinics Bethanien, Cologne, Germany
4. Department of Urology, Chemnitz and Malteser Hospital St. Hildegardis, Cologne, Germany
5. Department of Urinary Stone Laboratory, Institute of Laboratory Diagnostics, Vivantes Klinikum Friedrichshain, Berlin, Germany