1. Norwegian Institute of Public Health; Knowledge Centre for the Health Services; PO BOX 4404 Nydalen Oslo Norway
2. Sunnaas Rehabilitation Hospital; TRS National Resource Centre for Rare Disorders; Nesoddtangen Norway 1450
3. Norwegian Knowledge Centre for the Health Services; Prevention, Health Promotion and Organisation Unit; PO Box 7004 St Olavs Plass Oslo Norway 0130