1. U.S. Centers for Disease Control. Summary Health Statistics for U. S. Adults: National Health Interview Survey 2012. http://www.cdc.gov/nchs/data/series/sr_10/sr10_260.pdf. Published February 2014. Accessed October 6,2015.
2. A systematic review of the global prevalence of low back pain;D Hoy;Arthritis Rheum,2012
3. Liberty Mutual Research Institute for Safety. 2011 Liberty Mutual Workplace Safety Index.; 2016. https://www.libertymutualgroup.com/about-liberty-mutual-site/research-institute-site/Documents/2016WSI.pdf.
4. The assessment of chronic health conditions on work performance, absence, and total economic impact for employers;JJ Collins;J Occup Environ Med,2005
5. The natural history and risk factors of musculoskeletal conditions resulting in disability among US Army personnel;AE Lincoln;Work,2002