Kobus, Ryszard, Paweł Kliś, and Paweł Godlewski. “Maintenance of Lead-Acid Batteries Used in Telecommunications Systems”. Journal of Telecommunications and Information Technology 62, no. 4 (December 30, 2015): 106–113. Accessed July 30, 2026. https://jtit.pl/jtit/article/view/993.