WECHULI, D.; OKELO, B.; KANGOGO, W. Notions of Subspace Hypercyclicity of Direct Sum of Operators . International Journal of Open Problems in Computer Science and Mathematics, [S. l.], v. 18, n. 3, p. 95–112, 2025. Disponível em: https://ijopcm.icsrs.uk/index.php/journal/article/view/33. Acesso em: 21 jun. 2026.