1.
Zadiraka КV, Lоs GA. On the stability and instability of solutions of linear differential equations of the $n$th order with periodic coefficients. Ukr. Mat. Zhurn. [Internet]. 1966 Oct. 27 [cited 2025 Dec. 6];18(6):117-22. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/8467