RT Journal Article SR Electronic T1 Limitation to muscular activity in chronic obstructive pulmonary disease JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 6 OP 7 DO 10.1183/09031936.04.00038104 VO 24 IS 1 A1 K.J. Killian YR 2004 UL http://erj.ersjournals.com/content/24/1/6.abstract AB