TY - STAND AU - H. Mullerova AU - A. Shukla AU - A. Hawkins AU - J. Quint BT - BMJ Open DO - 10.1136/bmjopen-2014-006171 M1 - 12 PY - 2014 EP - e006171 T2 - BMJ Open TI - Risk factors for acute exacerbations of COPD in a primary care population: a retrospective observational cohort study VL - 4 SN - 2044-6055 ER -