TY  - RPRT
TI  - Missing hospital records: a confounding variable in retrospective studies.
AU  - M Westgren
AU  - M Divon
AU  - J Greenspoon
AU  - R Paul
PY  - 1986
DO  - 10.1016/0002-9378(86)90806-9
UR  - https://pubmed.ncbi.nlm.nih.gov/3740138/
ID  - 3740138
ER  -