TY  - RPRT
TI  - Directionality in epidemiologic research.
AU  - A R Feinstein
PY  - 1988
DO  - 10.1016/0895-4356(88)90153-9
UR  - https://pubmed.ncbi.nlm.nih.gov/3418357/
ID  - 3418357
ER  -