Краснодембський АМ. PERIODICITY OF DECISIONS OF SOME SYSTEM OF TWO NONLINEAR DIFFERENTIAL EQUALIZATIONS OF THE SECOND ORDER. Number [Internet]. 2019 Mar. 7 [cited 2025 Dec. 6];(1(9):21-5. Available from: https://pvntsh.nung.edu.ua/index.php/number/article/view/281