Não informado. (1975). British Journal of Obstetrics and Gynaecology. Royal College of Obstetricians and Gynaecologists.
Chicago-referens (17:e uppl.)Não informado. British Journal of Obstetrics and Gynaecology. London: Royal College of Obstetricians and Gynaecologists, 1975.
MLA-referens (8:e uppl.)Não informado. British Journal of Obstetrics and Gynaecology. Royal College of Obstetricians and Gynaecologists, 1975.
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