ALEXANDROV, G. On the three-spaces problem and extension of MLUR norms on Banach spaces. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 86, n. 1, p. 43–48, 1994. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/436. Acesso em: 24 nov. 2024.