TY  - RPRT
TI  - Acute exacerbations in chronic obstructive pulmonary disease (COPD)--microbial patterns and risk factors.
AU  - H Schäfer
AU  - S Ewig
PY  - 2000
UR  - https://pubmed.ncbi.nlm.nih.gov/11213381/
ID  - 11213381
ER  -