Authors
Mohammad Taghi Heydari
Department of Mathematics, College of Sciences, Yasouj University,, Yasouj, Iran
Department of Mathematics, College of Sciences, Higher Education Center of Eghlid,, Eghlid, Iran
© 2017 Mohammad Taghi Heydari, published by Ovidius University of Constanta
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.