Конін, В. В., В. Г. Мелкумян, and О. П. Сушич. “Satellite Navigating Systems Availability Estimation”. Problems of Informatization and Control 1, no. 12 (March 1, 2005): 90–93. Accessed October 19, 2026. https://jrnl.kai.edu.ua/index.php/PIU/article/view/11491.