TY  - RPRT
TI  - A structural approach to selection bias.
AU  - Miguel A Hernán
AU  - Sonia Hernández-Díaz
AU  - James M Robins
PY  - 2004
DO  - 10.1097/01.ede.0000135174.63482.43
UR  - https://pubmed.ncbi.nlm.nih.gov/15308962/
ID  - 15308962
ER  -