STRUŻAK, Ryszard. Trends in Use of RF Spectrum. Journal of Telecommunications and Information Technology, Warsaw, Poland, v. 38, n. 4, p. 95–100, 2009. DOI: 10.26636/jtit.2009.4.991. Disponível em: https://www.jtit.pl/jtit/article/view/991. Acesso em: 24 aug. 2026.