BEKKER, M. B. On a two-dimensional trigonometric moment problem. Methods of Functional Analysis and Topology, [S. l.], v. 9, n. 3, p. 185–188, 2003. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/214. Acesso em: 19 dec. 2025.