MORZHAKOV, V. On the applicability theory to differential operators of infinite order in spaces of functions of several variables. Lithuanian Mathematical Journal, [S. l.], v. 11, n. 4, p. 843–859, 1971. DOI: 10.15388/LMJ.1971.21038. Disponível em: https://www.journals.vu.lt/LMJ/article/view/21038.. Acesso em: 7 may. 2024.