Sruthi S, Deepa Gurunathan, and Subramanian E M G. “Working Length of Maxillary Primary First Molars in Children Aged 2-6 Years”. International Journal of Research in Pharmaceutical Sciences, vol. 11, no. (SPL 3), Oct. 2020, pp. 1552-7, https://ijrps.com/home/article/view/3205.