HefterSL, GoncharukAB. Linear differential equation with inhomogeneity in the form of a formal power series over a ring with non-Archimedean valuation. Ukr. Mat. Zhurn. [Internet]. 2022Dec.26 [cited 2024Nov.23];74(11):1463 -1477. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/7287