STECENKO, V.; CURCIC, D. Some conditions of the non-reducible operators. Lithuanian Mathematical Journal, [S. l.], v. 7, n. 4, p. 665–671, 1967. DOI: 10.15388/LMJ.1967.20015. Disponível em: https://www.journals.vu.lt/LMJ/article/view/20015.. Acesso em: 3 may. 2024.