KHADSHIIVANOV, N.; NIKIFOROV, V. On the theorems of Borsuk-Ulman and Ljusternik-Shnirelman-Borsuk. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 84, p. 83–89, 1993. Disponível em: https://admin.uni-sofia.bg/index.php/fmi/article/view/471. Acesso em: 16 jan. 2025.