1.
Hefter SL, Goncharuk AB. Linear differential equation with inhomogeneity in the form of a formal power series over a ring with non-Archimedean valuation. Ukr. Mat. Zhurn. [Internet]. 2022 Dec. 26 [cited 2025 Apr. 7];74(11):1463-77. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/7287