Osiri, S., P. Vibulcharoenkitja, D. Banomyong, K. Chotvorrarak, and S. Sutimuntanakul. “Bismuth Oxide Radiopacifier in Non-Mineral Trioxide Aggregate Calcium Silicate Cement: The Effect on Tooth Discoloration in a Regenerative Endodontic Tooth Model”. Mahidol Dental Journal, vol. 42, no. 2, July 2022, pp. 191-8, https://he02.tci-thaijo.org/index.php/mdentjournal/article/view/257734.