El Ghareeb, Abd El Wahab, Hamida Hamdi, Abdel-Latif Sweilam, and Niveen Ahmed. 2016. “Assessment of the Zygote and Cleaved Stages Frozen-Thawed Human Embryos by Vitrification and Their Survival to Blastocysts”. Asian Journal of Applied Sciences 4 (4). https://www.ajouronline.com/index.php/AJAS/article/view/4101.