García-Gonzales, L. A., and T. A. Evaristo-Chiyong. “Esthetic Perception of the Smile According to Variation of the Vertical Position and the Angulation of the Upper Central Incisor in Three Regions of Peru”. Odovtos - International Journal of Dental Sciences, vol. 22, no. 2, Mar. 2020, pp. 179-91, doi:10.15517/ijds.2020.41149.