TY  - RPRT
TI  - Choosing between randomised and non-randomised studies: a systematic review
AU  - MJ Campbell
PY  - 1998
DO  - 10.1136/bmj.317.7167.1258a
UR  - https://pubmed.ncbi.nlm.nih.gov/9794886/
ID  - 9794886
ER  -