Measurement of Pesticides and Other Toxicants in Amniotic Fluid as a Potential Biomarker of Prenatal Exposure: A Validation Study. - Bradman, Asa; Barr, Dana B.; Claus Henn, Birgit G.; Drumheller, Timothy; Curry, Cynthia; Eskenazi, Brenda (Environmental Health Perspectives, 2003)