OSTROVSKYI, V. L. On $*$-representations of a certain class of algebras related to a graph. Methods of Functional Analysis and Topology, [S. l.], v. 11, n. 3, p. 250–256, 2005. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/283. Acesso em: 16 dec. 2025.