WIERZBICKI, Andrzej P. Challenges before National Institute of Telecommunications after fifty years of its activity. Journal of Telecommunications and Information Technology, Warsaw, Poland, v. 4, n. 2, p. 3–9, 2001. DOI: 10.26636/jtit.2001.2.60. Disponível em: https://www.jtit.pl/jtit/article/view/60. Acesso em: 19 jun. 2026.