1. Department of Mathematics, Birla Institute of Technology and Science , Pilani, Rajasthan 333031, India
2. Department of Mathematics and Computer Sciences, Faculty of Arts and Sciences Cankaya University , Ankara TR-06530, Turkey ; , Magurle-Bucharest R-077125, Romania
3. Institute of Space Science , Ankara TR-06530, Turkey ; , Magurle-Bucharest R-077125, Romania