1. Department of Clinical Research, Sørlandet Hospital Trust, Post Box 416, Kristiansand N-4604, Norway
2. Department of Information and Communication Technology, University of Agder, Post Box 422, Kristiansand N-4604, Norway
3. Norwegian Centre for E-Health Research, University Hospital of North Norway, Post Box 35, Tromsø N-9038, Norway
4. Department of Community Medicine, The Arctic University of Norway, Post Box 6050 Langnes, Tromsø N-9037, Norway