L. A. García-Gonzales 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 - Int J Dent Sc, vol. 22, no. 2, pp. 179–191, Mar. 2020.