Roongruangchai, J., K. . Roongruangchai, and R. . Kolaka. “The Origin of Endoderm: Transmission Electron Microscopic Point of View”. Siriraj Medical Journal, vol. 62, no. 3, July 2020, pp. 124-7, https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/243766.