TY  - RPRT
TI  - Useful methods for sensitivity analysis of observational studies.
AU  - S Greenland
PY  - 1999
DO  - 10.1111/j.0006-341x.1999.00990.x
UR  - https://pubmed.ncbi.nlm.nih.gov/11315040/
ID  - 11315040
ER  -