1. Folic acid and the prevention of birth defects;Butterworth;Annu. Rev. Nutr.,1996
2. Folic acid and the prevention of birth defects;Moore,1993
3. Unintended pregnancy in the United States;Henshaw;Fam. Plann. Perspect.,1998
4. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects;Centers for Disease Control;MMWR,1992
5. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects;Food and Nutrition Board, Institute of Medicine,1998