BOGDANSKY, Yu. V. Essentially infinite-dimensional elliptic operators and P. Levy’s problem. Methods of Functional Analysis and Topology, [S. l.], v. 5, n. 4, p. 28–36, 1999. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/105. Acesso em: 18 dec. 2025.