The prevalence of quadriceps weakness in COPD and the relationship with disease severity
J.M. Seymour, M.A. Spruit, N.S. Hopkinson, S.A. Natanek, W.D-C. Man, A. Jackson, H.R. Gosker, A.M.W.J. Schols, J. Moxham, M.I. Polkey, E.F.M. Wouters
European Respiratory Journal Jul 2010, 36 (1) 81-88; DOI: 10.1183/09031936.00104909