KORNEICHUK, N. P. Permutations and piecewise-constant approximation of continuous functions of n variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 7, p. 907–918, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4871. Acesso em: 14 apr. 2025.