Corcoran, C., and D. R. Hardie. “Seroprevalence of Rubella Antibodies Among Antenatal Patients in the Western Cape”. South African Journal of Obstetrics and Gynaecology, vol. 12, no. 1, May 2006, pp. 26-28, https://www.ajol.info/index.php/sajog/article/view/34294.