Marchuk, Natalia, and Iryna Semenyshyna. “ABOUT THE INVARIANT TORS OF CALCULATION SYSTEMS OF DIFFERENTIAL EQUATIONS CONTAINING DEVIATIONS OF A DISCRETE ARGUMENT”. European Science 1, no. sge09-01 (February 28, 2022): 95–108. Accessed March 28, 2024. https://desymp.promonograph.org/index.php/sge/article/view/sge09-01-012.