Não informado. (2002). ACOG Practice Bulletin. American College of Obstetricians and Gynecologists.
Chicago-Zitierstil (17. Ausg.)Não informado. ACOG Practice Bulletin. Washington: American College of Obstetricians and Gynecologists, 2002.
MLA-Zitierstil (8. Ausg.)Não informado. ACOG Practice Bulletin. American College of Obstetricians and Gynecologists, 2002.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.