TY  - RPRT
TI  - Breathlessness during exercise in COPD: how do the drugs work?
AU  - P M A Calverley
PY  - 2004
DO  - 10.1136/thx.2004.023150
UR  - https://pubmed.ncbi.nlm.nih.gov/15170021/
ID  - 15170021
ER  -