University of Cologne, Department I of Internal Medicine, Cologne, Germany
Universtiy Hospital of Muenster, Internal Medicine A, Muenster, Germany
University of Würzburg, Würzburg, Germany
University of Cologne, Cologne, Germany
Ophthalmic Clinic, Rotterdam, Netherlands
University of Cologne, Cologne, Germany
Instituo Oftalmologico de Aragon, Zaragoza, Spain
University of Cologne, Cologne, Germany
Carl Gustav Carus University Hospital, Dresden, Germany
University of Heidelberg, Heidelberg, Germany
Medizinische Klinik II und Poliklinik für Innere Medizin, Cologne, Germany
Dept. of Anaesthesia and Transfusion Medicine, University of Tuebingen, Tuebingen, Germany
Health Care Centre, Dept. of Neurology, Johannes Gutenberg University of Mainz, Mainz, Germany
Interdisciplinary Dept. of Pain Management, Dept. of Anaesthesiology, Ludwig-Maximilians-University, Munich, Germany
Knappschaft Krankenhaus, Bochum-Langendreer, Germany
Praxis Fuer Haematologie Internistische Onkologie, Cologne, Germany
St. Elisabeth-Krankenhaus - Koeln, Cologne, Germany
Kreiskrankenhaus, Bad Hersfeld, Germany
Internistische Onkologische Praxis - Kronach, Kronach, Germany
Universitaetsklinikum Essen, Essen, Germany
University of Cologne, Dept. of Psychiatry and Psychotherapy, Cologne, NRW, Germany
University Hospital Brno, Brno, Czechia
Hopital Debrousse, Lyon, France
Charles University Hospital, Prague 5, Czechia