TY - JOUR AU - Jenkins C. AU - Postma D. AU - Anzueto A. AU - Make B. AU - Similowski T. AU - Ostlund O. AU - Eriksson G. AU - Calverley P BT - Respiratory Medicine ET - 15 Aug 2013 LA - eng M1 - 12 PY - 2013 SP - 1939 EP - 47 ST - Respir. Med. T2 - Respiratory Medicine TI - Factor analysis in predominantly severe COPD: Identification of disease heterogeneity by easily measurable characteristics. VL - 107 ER -