1. Epidemiology of chronic pain in Denmark: an update;Sjogren;Eur J Pain,2009
2. Chronic pain in Australia: a prevalence study;Blyth;Pain,2001
3. Comprehensive review of epidemiology, scope, and impact of spinal pain;Manchikanti;Pain Physician,2009
4. Pain management: fibromyalgia drugs are ‘as good as it gets’ in chronic pain;Clauw;Nat Rev Rheumatol,2010
5. Classification of chronic pain: descriptions of chronic pain syndromes and definitions of pain terms. Monograph for the task force of TAXONOMY;Merskey,1994