VALDAR, Andy. The Potential Cyber and Network Security Issues of PSTN Closure. Journal of Telecommunications and Information Technology, Warsaw, Poland, n. Special Issue, p. 18–24, 2025. DOI: 10.26636/jtit.2025.FITCE2024.2021. Disponível em: https://jtit.pl/jtit/article/view/2021. Acesso em: 17 jun. 2026.