TY  - RPRT
TI  - "Directionality" in epidemiologic research.
AU  - O S Miettinen
PY  - 1989
DO  - 10.1016/0895-4356(89)90093-0
UR  - https://pubmed.ncbi.nlm.nih.gov/2778462/
ID  - 2778462
ER  -