Краснодембський, А. М. (2019) “PERIODICITY OF DECISIONS OF SOME SYSTEM OF TWO NONLINEAR DIFFERENTIAL EQUALIZATIONS OF THE SECOND ORDER”, PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY. Number, (1(9), pp. 21–25. Available at: https://pvntsh.nung.edu.ua/index.php/number/article/view/281 (Accessed: 6 December 2025).