Мачалин, Игорь Алексеевич. “Сriterion of Periodicity of Checking Uptime of Telecommunications Systems”. Ukrainian Information Security Research Journal 14, no. 3 (56) (September 15, 2012): 25–28. Accessed April 24, 2026. http://jrnl.kai.edu.ua/index.php/ZI/article/view/3355.