RAMM, Alexander G. A simple proof of the closed graph theorem. Global Journal of Mathematical Analysis, [S. l.], v. 4, n. 1, p. 1–1, 2015. DOI: 10.14419/gjma.v4i1.5534. Disponível em: https://www.sciencepubco.com/index.php/GJMA/article/view/5534.. Acesso em: 28 apr. 2024.