CABRERA GONZÁLEZ, Y. V.; GARRIDO GUILLÁN, D.; GUILLÁN JOA, E. PROPOSAL FOR THE DESIGN OF A PABX USING FREE HARDWARE AND SOFTWARE. Telemática, [S. l.], v. 19, n. 1, p. 1–10, 2020. Disponível em: https://revistatelematica.cujae.edu.cu/index.php/tele/article/view/356. Acesso em: 26 sep. 2021.