Kowalczyk, Stanisław. “PDHdtjtd Systemy PDH Ss: Sieci WAN Nowa Poprawka Tstjsttj”. DEMO 12304, no. 130 (June 25, 2021). Accessed September 20, 2024. https://ojs34.fimagis.pl/index.php/demo/article/view/69.