Wright, Janis. Pregnancy: Prenatal Care. American Family Physician (American Academy of Family Physicians). September 15, 2003, 68 (6): 1165–1167 [2017-08-19]. (原始内容存档于2008-05-15).
Wright, Janis. Pregnancy: Prenatal Care. American Family Physician (American Academy of Family Physicians). September 15, 2003, 68 (6): 1165–1167 [2017-08-19]. (原始内容存档于2008-05-15).