À propos de cet article
Publié en ligne: 02 déc. 2020
Pages: 287 - 293
Reçu: 17 déc. 2019
DOI: https://doi.org/10.2478/ausm-2020-0020
Mots clés
© 2020 Peter V. Danchev, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Danchev, Peter V.
Institute of Mathematics and Informatics, Bulgarian Academy of SciencesSofia, Bulgaria