1. Bremen Institute for Prevention Research and Social Medicine; Clinical Epidemiology; Achterstrasse 30 Bremen Germany 28359
2. Charité - Universitätsmedizin Berlin; Med. Klinik I; Campus Benjamin Franklin Hindenburgdamm 30 Berlin Germany 12203
3. Institute of Medical Biometry and Medical Informatics, University Medical Center Freiburg; German Cochrane Centre; Stefan-Meier-Str. 26 Freiburg Germany 79104
4. Universitätsklinikum Schleswig-Holstein, Campus Lübeck; Lubeck Germany
5. Medical University of Vienna; Clinic of Internal Medicine III; Waehringer Guertel 18-20 A-1090 Vienna Austria