YAMPOLSKY, A. Full description of totally geodesic unit vector fields on 2-dimensional Riemannian manifolds. Математическая физика, анализ, геометрия, Харків, Україна, v. 11, n. 3, p. 355–365, 2004. Disponível em: http://mag.ilt.kharkiv.ua/index.php/mag/article/view/m11-0355e. Acesso em: 22 груд. 2024.