1. Waddell G, Norlund AI (2000) Review of Social Security. In: Nachemson A and Jonsson E (eds). Neck and Back Pain: The scientific evidence of causes, diagnosis and treatment. JB Lippincott: Philadelphia, p427–71
2. Ekberg K, Wildhagen I (1996) Long-term sickness absence due to musculoskeletal disorders: the necessary intervention of work conditions. Scand J Rehab Med 28: 39–47
3. Burri M (2002) Statistiques de la Sécurité Sociale. Statistiques de l’AI 2002. Office Fédéral des Assurances Sociales (OFAS), p2–40
4. Bonfiglio RP, LaBan MM, Taylor RS et al. (1993) Industrial Rehabilitation Medicine management. In: DeLisa ed. Rehabilitation Medicine. Principles and Practice. JB Lippincott: Philadelphia, p169–77
5. Engström LG, Eriksen T (2002) Can difference in benefit levels explain duration and outcome of sickness absence? Disabil Rehabil 24(14): 713–18