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 1211 OP 1214 VO 13 IS 5 A1 Folgering, H YR 1999 UL http://erj.ersjournals.com/content/13/5/1211.abstract AB