Nonexistence of orbital morphisms between dynamical systems on spheres. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 83, n. 1, p. 123–128, 1992. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/492. Acesso em: 12 jan. 2026.