About this article
Published Online: Oct 02, 2020
Page range: 255 - 265
Received: Jun 10, 2020
Accepted: Sep 14, 2020
DOI: https://doi.org/10.2478/mjpaa-2020-0020
Keywords
© 2020 T. M. Al-shami, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Al-shami, T. M.
Department of Mathematics, Sana’a University, Sana’aYemen