Yodmanotham, P., and N. Wongwatanasanti. “The gutta-percha softening efficacy of synthetic D-limonene at different concentrations and contact times”. Mahidol Dental Journal, vol. 40, no. 1, Apr. 2020, pp. 8-14, https://he02.tci-thaijo.org/index.php/mdentjournal/article/view/190213.