Core outcome measurement instruments for clinical trials in nonspecific low back pain

Alessandro Chiarotto, Maarten Boers, Richard A. Deyo, Rachelle Buchbinder, Terry P. Corbin, Leonardo O.P. Costa, Nadine E. Foster, Margreth Grotle, Bart W. Koes, Francisco M. Kovacs, C. W. Christine Lin, Chris G. Maher, Adam M. Pearson, Wilco C. Peul, Mark L. Schoene, Dennis C. Turk, Maurits W. Van Tulder, Caroline B. Terwee, Raymond W. Ostelo