À propos de cet article
Publié en ligne: 04 mars 2019
Pages: 242 - 248
Reçu: 06 juil. 2017
DOI: https://doi.org/10.2478/ausm-2018-0019
Mots clés
© 2018 C. Carpintero et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
The aim of this paper is to introduce and study upper and lower