1. Vascular Institute Central Switzerland, Aarau, Switzerland / Department of Angiology, University Hospital and University of Basel, Switzerland
2. Angiologia, Ospedale Regionale di Locarno, Switzerland
3. Department of Angiology, University Hospital and University of Basel, Switzerland
4. Vascular Institute Central Switzerland, Aarau, Switzerland
5. Gefässmedizin Rapperswil, Switzerland
6. Vein Center Arlesheim, Arlesheim, Switzerland
7. Department of Angiology, University Hospital and University of Basel, Switzerland / Gefässpraxis am See – Lakeside Vascular Centre, Lucerne, Switzerland