1.
Оrосhkо YВ. On the powers of an operator of an engendered Cauchy problem for a hyperbolic equation of the second order. Ukr. Mat. Zhurn. [Internet]. 1966 Jun. 28 [cited 2025 Dec. 6];18(4):34-48. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/8311