Authors
Rovana Boruga
Department of Mathematics, West University of Timişoara, Timişoara, Romania
Mihail Megan
Academy of Romanian Scientists, West University of Timişoara, Timişoara, Romania
© 2020 Rovana Boruga, Mihail Megan, published by West University of Timisoara
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.