RT Journal Article SR Electronic T1 CO2-response in chronic obstructive pulmonary disease JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1212 OP 1214 VO 13 IS 5 A1 Begin, P A1 Grassino, A YR 1999 UL http://erj.ersjournals.com/content/13/5/1212.abstract AB