1. Plutarch: Lycurgus 14 (trans. John Dryden). New York: Random House; 1932. p. 59–60.
2. Old Testament (Judges 13:3–4).
3. US Department of Health, Education and Welfare (PHS) HAS/BCHS. Primary care effectiveness—An approach to clinical quality assurance in BCHS programs and projects, Washington, DC: Author; January, 1979.
4. Institute of Medicine Committee to Study the Prevention of Low Birthweight. Preventing low birthweight. Washington, DC: National Academy Press; 1985.
5. U.S. Public Health Service Expert Panel on Prenatal Care. Caring for our future: the content of prenatal care. Washington, DC: Public Health Service. Department of Health and Human Services; 1989.