Authors
Nazi Abachi
Department of Mathematics, Central Tehran Branch, Islamic Azad University Tehran
Shervin Sahebi
Department of Mathematics, Central Tehran Branch, Islamic Azad University Tehran, Iran
© 2020 Nazi Abachi, Shervin Sahebi, published by Ovidius University of Constanta
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.