The Lower Densities of Symmetric Perfect Sets. Analysis in Theory and Applications, [S. l.], v. 28, n. 4, p. 377–384, 2012. DOI: 10.3969/j.issn.1672-4070.2012.04.006. Disponível em: https://www.global-sci.com/index.php/ata/article/view/7964. Acesso em: 6 dec. 2025.