JANIN, D.; LENZI, G. On the logical definability of topologically closed recognizable languages of infinite trees. COMPUTING AND INFORMATICS, [S. l.], v. 21, n. 3, p. 185–203, 2012. Disponível em: https://www.cai.sk/ojs/index.php/cai/article/view/495. Acesso em: 4 feb. 2023.