Não informado. (2002). ACOG technical bulletin. American College of Obstetricians and Gynecologists.
Chicago-referens (17:e uppl.)Não informado. ACOG Technical Bulletin. Washington: American College of Obstetricians and Gynecologists, 2002.
MLA-referens (8:e uppl.)Não informado. ACOG Technical Bulletin. American College of Obstetricians and Gynecologists, 2002.
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