Khadshiivanov, Nikolay, and Vladimir Nikiforov. “On the Theorems of Borsuk-Ulman and Ljusternik-Shnirelman-Borsuk”. Ann. Sofia Univ. Fac. Math. and Inf. 84 (December 12, 1993): 83–89. Accessed November 22, 2024. https://annual.uni-sofia.bg/index.php/fmi/article/view/471.