Positive Definite and Related Functions in the Product of Hypercomplex Systems. Global Journal of Science Frontier Research, [S. l.], v. 17, n. F2, p. 49–61, 2017. Disponível em: https://www.journalofscience.org/index.php/GJSFR/article/view/2020. Acesso em: 5 feb. 2026.