TY  - RPRT
TI  - Selection bias in epidemiologic studies.
AU  - D G Kleinbaum
AU  - H Morgenstern
AU  - L L Kupper
PY  - 1981
DO  - 10.1093/oxfordjournals.aje.a113113
UR  - https://pubmed.ncbi.nlm.nih.gov/6971055/
ID  - 6971055
ER  -