Yampolsky, Alexander L. “Minimal and Totally Geodesic Unit Sections of the Unit Sphere Bundles”. Visnyk of V. N. Karazin Kharkiv National University. Ser. Mathematics, Applied Mathematics and Mechanics0, no. 1030 (November 24, 2012): 54-70. Accessed May 4, 2024. https://periodicals.karazin.ua/mech_math/article/view/13162.