1. Department of Mathematics, Basic Science Faculty, University of Bonab, Bonab, Iran
2. Department of Mathematics, Science Faculty, Firat University, Elazig, Turkey
3. Department of Mathematics, Faculty of Arts and Sciences, Cankaya University, Ankara, Turkey + Institute of Space Sciences, Magurele-Bucharest, Romania + Department of Mathematics and Statistics, Faculty of Science, Tshwane University of Technology, Pretor