Т. Тепнадзе 2021. Ces`aro means of negative order of the one-dimensional Vilenkin-Fourier series. Bulletin of L.N. Gumilyov Eurasian National University. Mathematics, computer science, mechanics series. 135, 2 (Jun. 2021), 6–11. DOI:https://doi.org/10.32523/bulmathenu.2021/2.1.