Slyusarchuk, V. Yu. “Necessary and Sufficient Conditions for the Absolute Instability of Solutions of Linear Differential-Difference Equations With Self-Adjoint Operator Coefficients”. Ukrains’kyi Matematychnyi Zhurnal 70, no. 5 (May 25, 2018): 715–724. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/1590.