Klinikverbund Allgäu, Kempten, BaBaden-Württembergs, Germany
Frankfurt Universitätsklinikum, Frankfurt, Hessen, Germany
Klinik für Strahlentherapie, Cyberknife und Radioonkologie Universität zu Köln, Cologne, NRW, Germany
University of California Los Angeles, Los Angeles, California, United States
University of Bern, Bern, Switzerland
Massachusetts General Hospital, Boston, Massachusetts, United States
Department of Functional Upper GI Surgery, Cologne, NRW, Germany
Department of Anesthesiology and Intensive Care Medicine, Cologne, NRW, Germany
University Hospital of Cologne and St. Elizabeth Hospital, Cologne, NRW, Germany
University Hospital Cologne, Cologne, Germany
Department II of Internal Medicine,University of Cologne, Cologne, Germany
Department of Ophthalmology, Aarhus University Hospital, Aarhus N, Midtjylland, Denmark
Klinik für Ophthalmologie des Universitätsklinikums Köln, Köln, NRW, Germany
Radboud-Universität Nijmegen, Nijmegen, Gelderland, Netherlands