Rodanant, P., T. Langlongsathit, W. Sermkasemsin, O. Leysak, and R. Surarit. “The effect of LED light on viability and proliferation of periodontal ligament fibroblast cells”. Mahidol Dental Journal, vol. 37, no. 1, Dec. 2016, pp. 23-28, https://he02.tci-thaijo.org/index.php/mdentjournal/article/view/179996.