1. The single umbilical artery;Ainsworth, P.; Davies, P.A.;Developmental Medicine and Child Neurology,1969
2. The occurrence of a non-allantoic or vitelline placenta in the human subject;Ballantyne, J.W.;Transactions of the Edinburgh Obstetrical Society,1898
3. The incidence and prognostic implication of congenital absence of one umbilical artery;Benirschke, K.; Bourne, G.L.;American_Journal of Obstetrics and Gynecology,1960
4. A vascular anomaly of the umbilical cord;Benirschke, K.; Brown, W.H.;Obstetrics and Gynecology,1955
5. The Pathology of the Human Placenta. (Reprint from Handbuch der Speziellen Pathologischen Anatomie und Histologie, Vol;Benirschke, K.; Driscoll, S.G.;VII,1967