TY  - RPRT
TI  - Compared to what? Finding controls for case-control studies.
AU  - David A Grimes
AU  - Kenneth F Schulz
DO  - 10.1016/s0140-6736(05)66379-9
UR  - https://pubmed.ncbi.nlm.nih.gov/15836892/
ID  - 15836892
ER  -