TY  - GEN
AU  - Lieff,S
AU  - Olshan,A F
AU  - Werler,M
AU  - Savitz,D A
AU  - Mitchell,A A
TI  - Selection bias and the use of controls with malformations in case-control studies of birth defects
SN  - 1044-3983
PY  - 1999///0614
KW  - Boston
KW  - epidemiology
KW  - Case-Control Studies
KW  - Cleft Lip
KW  - Cleft Palate
KW  - Congenital Abnormalities
KW  - Environmental Exposure
KW  - adverse effects
KW  - Female
KW  - Humans
KW  - Infant, Newborn
KW  - Ontario
KW  - Philadelphia
KW  - Population Surveillance
KW  - Pregnancy
KW  - Pregnancy Complications
KW  - Pregnancy Trimester, First
KW  - Prevalence
KW  - Research Design
KW  - Risk Factors
KW  - Selection Bias
KW  - Smoking
N1  - Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S
ER  -