Any of these:
1.Opioid use in fibromyalgia is associated with negative health related measures in a prospective cohort study.Fitzcharles MA, Faregh N, Ste-Marie PA, Shir Y.
Pain Res Treat. 2013;2013:898493. doi: 10.1155/2013/898493. Epub 2013 Mar 18.
2. Chronic opioid use in fibromyalgia syndrome: a clinical review.
Painter JT, Crofford LJ.
J Clin Rheumatol. 2013 Mar;19(2):72-7. doi: 10.1097/RHU.0b013e3182863447.
PMID: 23364665 [PubMed - in process]
3.Opioid use, misuse, and abuse in patients labeled as fibromyalgia.
Fitzcharles MA, Ste-Marie PA, Gamsa A, Ware MA, Shir Y.
Am J Med. 2011 Oct;124(10):955-60. doi: 10.1016/j.amjmed.2011.05.031.
4.The use of opioids in fibromyalgia.Ngian GS, Guymer EK, Littlejohn GO.
Int J Rheum Dis. 2011 Feb;14(1):6-11. doi: 10.1111/j.1756-185X.2010.01567.x. Epub 2010 Aug 23. Review.