D. T. Gray, R. A. Deyo, W. Kreuter, S. K. Mirza, P. J. Heagerty, B. A. Comstock and L. Chan, “Population-Based Trends in Volumes and Rates of Ambulatory Lumbar Spine Surgery,” Spine, Vol. 31, No. 17, 1964, pp. 1957-1963. doi:10.1097/01.brs.0000229148.63418.c1
 P. J. Watson, C. K. Booker, L. Moores and C. J. Main, “Returning the Chronically Unemployed with Low Back Pain to Employment,” European Journal of Pain, Vol. 8, No. 4, 2004, pp. 359-369. doi:10.1016/j.ejpain.2003.11.003
 P. L. Sanderson, B. D. Todd, G. R. Holt and C. J. Getty, Compensation, Work Status, and Disability in Low Back Pain Patients,” Spine, Vol. 20, No. 5, 1995, pp. 554-556. doi:10.1097/00007632-199503010-00009
 M. S. Walid, J. S. Robinson, M. Abbara, A. Tolaymat and J. S. Jr. Robinson, “De Novo Spine Surgery as a Predictor of Additional Spine Surgery at the Same or Distant Spine Regions,” German Medical Science, Vol. 9, 2011, p. 20.
 S. E. Back, R. L. Payne, A. H. Wahlquist, R. E. Carter, Z. Stroud, L. Haynes, M. Hillhouse, K. T. Brady and W. Ling, “Comparative Profiles of Men and Women with Opioid Dependence: Results from a National Multisite Effectiveness Trial,” American Journal of Drug and Alcohol Abuse, Vol. 37, No. 5, 2011, pp. 313-323. doi:10.3109/00952990.2011.596982
 M. Tournier, A. Cougnard, S. Boutouaba-Combe and H. Verdoux, “Duration of Antidepressant Drug Treatment and Its Determinants in France,” Encephale, Vol. 37, Suppl. 1, 2011, pp. S36-S41. doi:10.1016/j.encep.2010.06.007
 E. Stranges, C. A. Russo and B. Friedman, “Procedures with the Most Rapidly Increasing Hospital Costs, 2004-2007,” Healthcare Cost and Utilization Project (HCUP) Statistical Briefs, Agency for Health Care Policy and Research, Rockville, 2006-2009.
 R. A. Deyo and Y. J. Tsui-Wu, “Descriptive Epidemiology of Low-Back Pain and Its Related Medical Care in the United States,” Spine, Vol. 12, No. 9, 1987, pp. 264-268. doi:10.1097/00007632-198704000-00013