1. American College of Obstetricians and Gynecologists. Standards for obstetric-gynecologic services,1985
2. Recommendations concerning supplement usage: ADA statement;American Dietetic Association;J. Am. Diet. Assoc.,1987
3. Statement of vitamin and mineral supplements;Callaway;J. Nut.,1987
4. Subcommittee on Dietary Intake and Nutrient Supplements during Pregnancy, Nutrition during pregnancy: Part I: weight gain, Part II: nutrient supplements,1990
5. Dietary Reference Intakes, Standing Committee on the Scientific Evaluation of the Dietary Reference Intakes (1998-2005), Food and Nutrition Board, Institute of Medicine, National Academy of Sciences, National Academy Press.