1. American College of Obstetricians and Gynecologists 2015 Health care for unauthorized immigrants https://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Health-Care-for-Underserved-Women/Health-Care-for-Unauthorized-Immigrants
2. Mostly Harmless Econometrics
3. Prepregnancy obesity and birth outcomes;Averett;Maternal & Child Health Journal,2016
4. Centers for Disease Control and Prevention 2008 Birth defects data and statistics http://www.cdc.ncbddd/birthdefects/data.html
5. Centers for Disease Control and Prevention 2013 Guidance for preventing birth defects http://www.cdc.gov/ncbddd/birthdefects/prevention.html