TY  - RPRT
TI  - Controlling confounding when studying large pharmacoepidemiologic databases: a case study of the two-stage sampling design.
AU  - J P Collet
AU  - D Schaubel
AU  - J Hanley
AU  - C Sharpe
AU  - J F Boivin
PY  - 1998
DO  - 10.1097/00001648-199805000-00011
UR  - https://pubmed.ncbi.nlm.nih.gov/9583424/
ID  - 9583424
ER  -