RT Journal Article SR Electronic T1 Physical activity in patients with chronic obstructive pulmonary disease JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society DO 10.1183/09031936.00024608 A1 H. Watz A1 B. Waschki A1 T. Meyer A1 H. Magnussen YR 2008 UL http://erj.ersjournals.com/content/early/2008/11/14/09031936.00024608.abstract AB