ZAGORODNYUK, Sergey. On extensions of commuting tuples of symmetric and isometric operators. Serdica Mathematical Journal, Sofia, Bulgaria, v. 46, n. 1, p. 19–34, 2020. Disponível em: https://serdica.math.bas.bg/index.php/serdica/article/view/199. Acesso em: 2 nov. 2026.