1. Department for Dermatology, University of Heidelberg, Heidelberg, Germany
2. Venenzentrum der Dermatologischen und Gefaßchirurgischen Kliniken, Bochum, Germany
3. Venenzentrum Freiburg, Freiburg, Germany
4. Praxis fur Innere Medizin und Gefaßkrankheiten, Halle/Saale, Halle, Germany
5. Venenzentrum am Bruhl, Leipzig, Germany
6. MVZ Dr. Ph. Zollmann & Kollegen, Jena, Germany
7. Venenzentrum Pforzheim, Pforzheim, Germany
8. Venen-Fachpraxis Regensburg, Regensburg, Germany
9. Dermatologikum Hamburg, Hamburg, Germany
10. Private Practice Dermatology and Phlebology, Bonn, Germany
11. Institute of Medical Biometry, University of Heidelberg, Heidelberg, Germany