PATIL, Vinayak L. Historical Perspectives of Development of Antique Analog Telephone Systems. Journal of Telecommunications and Information Technology, [S. l.], v. 61, n. 3, p. 70–98, 2015. DOI: 10.26636/jtit.2015.3.973. Disponível em: https://jtit.pl/jtit/article/view/973. Acesso em: 17 apr. 2026.