About this article
Published Online: Dec 31, 2020
Page range: 116 - 125
Received: Sep 25, 2020
Accepted: Nov 04, 2020
DOI: https://doi.org/10.2478/cait-2020-0066
Keywords
© 2020 Nikolay Shegunov et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Shegunov, Nikolay
Kaiserslautern, Germany
Sofia UniversitySofia, Bulgaria
Iliev, Oleg
Kaiserslautern, Germany
Institute of MathematicsSofia, Bulgaria