Tian YL, Liu F, Sun HJ, Lv P, Cao YM, Yu M, , Yue Y.  Alveolar bone thickness around maxillary central incisors of different inclination assessed with cone-beam computed tomography.  Korean J Orthod 2015;45:245-252.  https://doi.org/10.4041/kjod.2015.45.5.245