1. Woolf AD, Pfleger B (2003) Burden of major musculoskeletal conditions. Bull World Health Organ 81:646–656
2. Fordyce W (1995) Back pain in the workplace: management of disability in nonspecific conditions: task force on pain in the workplace. IASP Press, Seattle
3. Frymoyer JW, Cats-Baril WL (1991) An overview of the incidences and costs of low back pain. Orthop Clin North Am 22:263–271
4. Waddell G (1998) The back pain revolution. Churchill Livingstone, Edinburgh
5. COST B (2006) European guidelines for the management of acute nonspecific low back pain in primary care. Eur Spine J 15(Suppl 2):S125–S300