POGORUI , A. A. Limiting incorrect equations in the Hilbert space. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 43, n. 2, p. 241–247, 2025. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/9364. Acesso em: 17 feb. 2026.