Murillo, Margarita, et al. “Comparison of Chu’s Proportion Gauge With a T-Bar Tip and a Two-Tip Compass in the Determination of Anterior Dentition Tooth Size in a Group of Puerto Ricans”. Puerto Rico Health Sciences Journal, vol. 39, no. 4, Dec. 2020, pp. 288-93, https://prhsj.rcm.upr.edu/index.php/prhsj/article/view/1749.