Cumulative occupational lumbar load and lumbar disc disease--results of a German multi-center case-control study (EPILIFT).
Seidler A, Bergmann A, Jäger M, Ellegast R, Ditchen D, Elsner G, Grifka J, Haerting J, Hofmann F, Linhardt O, et al. BMC Musculoskelet Disord. 2009 May 7; 10:48. Epub 2009 May 7.