1. Witten/Herdecke University; Institute for Research in Operative Medicine (IFOM) - Department for evidence based health services research; Ostmerheimer Str. 200 (Building 38) Cologne NRW Germany 51109
2. Carl von Ossietzky University Oldenburg; Department of Health Services Research; Ammerländer Heerstrasse 140 Oldenburg Saxony Germany 26111
3. Danube University Krems; Cochrane Austria, Department for Evidence-based Medicine and Evaluation; Dr.-Karl-Dorrek-Straße 30 Krems Austria 3500a