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Crabtree KL, Spurgeon A, Arzi H, Beaver B, Arnold PM.Crabtree KL, et al.Evid Based Spine Care J. 2011 May;2(2):49-54. doi: 10.1055/s-0030-1267105.Evid Based Spine Care J. 2011.PMID: 23637682Free PMC article.