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1 2 (Inggeris) Charles Rb Beckmann, American College of Obstetricians and Gynecologists, Barbara M Barzansky, Frank W Ling, Douglas W Laube (2009). Obstetrics and Gynecology. Lippincott Williams & Wilkins Publishers. ISBN 978-0-7817-8807-6.Selenggaraan CS1: pelbagai nama: senarai pengarang (link)Page.121-123
↑ (Inggeris) Marie Bakitas Whedon, Debra Wujcik (1997). Blood Marrow Stem Cell Transplant 2E. Jones & Bartlett Publishers. m/s. 63-64. ISBN 978-0-7637-0356-1.
↑ "Fetal Circulation". www.heart.org. Diarkib daripada yang asal pada 22 December 2017. Dicapai pada 27 March 2018.
