Introduction of the topology structure in Fréchet and Hausdorff works. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales, Bogotá, Colombia, v. 41, n. 161, p. 528–537, 2018. DOI: 10.18257/raccefyn.510. Disponível em: https://raccefyn.co/index.php/raccefyn/article/view/510. Acesso em: 9 mar. 2025.