BIKELIS, A. On the multivariate characteristic functions. Lithuanian Mathematical Journal, [S. l.], v. 8, n. 1, p. 21–39, 1968. DOI: 10.15388/LMJ.1968.20178. Disponível em: https://www.journals.vu.lt/LMJ/article/view/20178.. Acesso em: 19 jul. 2024.