About this article
Published Online: Jan 21, 2022
Page range: 57 - 61
Received: Mar 17, 2021
Accepted: Jul 07, 2021
DOI: https://doi.org/10.2478/aupcsm-2021-0004
Keywords
© 2021 Anna Gąsior et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License.
Gąsior, Anna
Institute of Mathematics, Maria Curie-Skłodowska UniversityLublin, Poland
Szczepański, Andrzej
Institute of Mathematics, University of GdańskGdańsk, Poland