Demchenko, B., A. Komarov, and L. Ussoltseva. “Robust Method for Determining the Orbits of Geostationary Satellites With a Lack of Data”. Recent Contributions to Physics, vol. 2016, no. 3, Sept. 2016, pp. 120-4, https://bph.kaznu.kz/index.php/zhuzhu/article/view/922.