TY  - RPRT
TI  - Matching in retrospective studies.
AU  - R J Hardy
AU  - C White
PY  - 1971
DO  - 10.1093/oxfordjournals.aje.a121235
UR  - https://pubmed.ncbi.nlm.nih.gov/5543533/
ID  - 5543533
ER  -