About this article
Published Online: Dec 25, 2020
Page range: 93 - 98
Received: Mar 08, 2019
Accepted: Nov 04, 2020
DOI: https://doi.org/10.2478/udt-2020-0012
Keywords
© 2020 Vsevolod F. Lev, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Lev, Vsevolod F.
Department of Mathematics, The University of Haifa at OranimTivon, Israel