KOROBEINIK, J. F. On some integral operator. Lithuanian Mathematical Journal, [S. l.], v. 5, n. 1, p. 97–115, 1965. DOI: 10.15388/LMJ.1965.19544. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19544.. Acesso em: 5 may. 2024.