PARASYUK, O. S. On an analytical consequence of the condition of unitariness. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 18, n. 6, p. 128–129, 1966. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8469. Acesso em: 6 dec. 2025.