On the theorems of Borsuk-Ulman and Ljusternik-Shnirelman-Borsuk. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 84, p. 83–89, 1993. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/471. Acesso em: 17 mar. 2026.