Team, S. “A Spherically Vicinal Mapping on Geodesic Spaces With Curvature Bounded Above: Takuto Kajimura, Yasunori Kimura”. Thai Journal of Mathematics, vol. 18, no. 1, Mar. 2020, pp. 384-93, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/1004.