ZIKKOS, E. Characterizing Riesz bases via biorthogonal Bessel sequences. Carpathian Mathematical Publications, [S. l.], v. 15, n. 2, p. 377–380, 2023. DOI: 10.15330/cmp.15.2.377-380. Disponível em: https://vps.pnu.edu.ua/index.php/cmp/article/view/5677. Acesso em: 21 nov. 2024.