1. Department of Physics, Faculty of Science, the University of Maroua, P.O. Box 814, Maroua, Cameroon
2. Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde-Cameroon
3. Department of Basic Science, Faculty of Mines and Petroleum Industries, University of Maroua, Maroua-Cameroon
4. Department of Mathematics, Firat University, Science Faculty, 23119 Elazig, Turkey
5. Department of Physics, Faculty of Science, The University of Ngaoundere, P.O. Box 454, Ngaoundere, Cameroon
6. Department of Physics, Laboratory of Mechanics, Materials and Structures, University of Yaounde I, Cameroon
7. Center of Excellence in Information and Communication Technologies (CETIC), University of Yaounde I, Yaounde, Cameroon
8. Department of Mathematics, Cankaya University, Ankara, Turkey
9. Institute of Space Sciences, Magurele-Bucharest, Romania
10. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
11. Department of Mathematics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia