TY  - RPRT
TI  - Observational studies and randomized trials.
AU  - R Kunz
AU  - K S Khan
AU  - H H Neumayer
PY  - 2000
DO  - 10.1056/nejm200010193431613
UR  - https://pubmed.ncbi.nlm.nih.gov/11041757/
ID  - 11041757
ER  -