Bu, Jingjing, Pan Jiang, Xiaoli Cui, Hongyan Zhou, and Fengxia Han. “Application Values of Prenatal Screening and Non‑invasive gene Sequencing in Fetal Birth Defects”. Pakistan Journal of Medical Sciences 36, no. 7 (October 17, 2020). Accessed October 21, 2020. http://www.pjms.org.pk/index.php/pjms/article/view/2290.