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://journals.vu.lt./LMJ/article/view/19544. Acesso em: 27 apr. 2025.