1. Botto LD, Olney RS, Erickson JD. Vitamin supplements and the risk for congenital anomalies other than neural tube defects. Am J Med Genet C 2004; 125C: 12–21.
2. Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. 7th ed. Lippincott Williams and Wilkins, Philadelphia, 2005.
3. Creasy RK, Resnik R, Iams JD (eds.) Maternal-Fetal Medicine. Principles and Practice. 5th ed. Saunders, Philadelphia, 2004.
4. Friedman JM, Polifka JE. The Effects of Drugs on the Fetus and Nursing Infant. Johns Hopkins Univ Press, Baltimore, 2000.
5. Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm birth. Lancet 2008; 371: 75–84.