1. Swiss Paraplegic Research; Nottwil Switzerland
2. University of Lucerne; Department of Health Sciences and Health Policy; Frohburgstrasse 3 Lucerne Switzerland CH-6002
3. Maastricht University; Department of Epidemiology; P.O. Box 616 Maastricht Netherlands 6200 MD
4. Swiss Paraplegic Foundation; Guido A Zäch Strasse 10 Nottwil Switzerland 6207
5. Lausanne University Hospital; Cochrane Switzerland, Institute of Social and Preventive Medicine; Route de la Corniche 10 Lausanne Switzerland CH-1010