1. VASCERN HHT Reference Centre, Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-Universität Marburg, Baldingerstrasse, Marburg 35043, Germany
2. Morbus Osler-Selbsthilfe e.V. (German HHT Self-Help Group), Berlin, Germany
3. Department of Oral and Maxillofacial Plastic Surgery, University-Hospital Aachen, RWTH Aachen, Pauwelsstraße 30, Aachen 52074, Germany
4. Department of Oral Surgery and Dental Emergency Care, School of Dentistry, Faculty of Health, Witten/Herdecke University, Alfred-Herrhausen-Strasse 44, Witten 58455, Germany
5. Arkansas College of Osteopathic Medicine, Fort Smith, AR, USA
6. VASCERN HHT Reference Centre, Department of Otorhinolaryngology, Head and Neck Surgery, Essen University Hospital, University Duisburg-Essen, Hufelandstrasse 55, Essen 45122, Germany