DUNCAN, Benton L. When universal separated graph $C^*$-algebras are exact. Methods of Functional Analysis and Topology, [S. l.], v. 26, n. 2, p. 126–140, 2020. DOI: https://doi.org/10.31392/MFAT-npu26_2.2020.05. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/753. Acesso em: 16 dec. 2025.