1.
HefterSL, Piven’ OL. Infinite order differential operators in the module of formal generalized functions and in a ring of formal power series. Ukr. Mat. Zhurn. [Internet]. 2022Jul.7 [cited 2024Dec.22];74(6):784 -799. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/6955