Hammash, M. Hayawi. “Early Embryology of the Prechordal Region”. Journal of the Faculty of Medicine Baghdad 47, no. 1 (April 3, 2005): 68–72. Accessed April 29, 2025. https://www.iqjmc.uobaghdad.edu.iq/index.php/19JFacMedBaghdad36/article/view/1684.