TOKAR, L. . Features of building virtual PBX. Radiotekhnika, [S. l.], v. 1, n. 208, p. 55–64, 2022. DOI: 10.30837/rt.2022.1.208.06. Disponível em: http://rt.nure.ua/article/view/257177. Acesso em: 13 may. 2025.