1. Department of Urology, University Medical Centre Freiburg, Freiburg, Germany
2. Fraunhofer Institute for Physical Measurement Techniques, Freiburg, Germany
3. Institute of Medical Biometry and Medical Informatics, University Medical Centre Freiburg, Freiburg, Germany
4. Institute of Laboratory Medicine, Carl-Thiem-Klinikum Cottbus, Cottbus, Germany
5. German Urinary Stone Analysis Centre Bonn, Bonn, Germany
6. Department of Urology and Pediatric Urology, University of Heidelberg, SLK Kliniken Heilbronn, Heilbronn, Germany