M. F. Aktaş, “Lyapunov-type inequalities for two classes of nonlinear systems with homogeneous Dirichlet boundary conditions”, Ukr. Mat. Zhurn., vol. 70, no. 6, pp. 727–738, Jun. 2018, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1591