1. Data Recovery Key Laboratory of Sichuan Province , College of Mathematics and Information Science , Neijiang Normal University , Neijiang , 641100 , PR China
2. Department of Mathematics , Cankaya University , 06530 Balgat , Ankara , Turkey
3. College of Mechanics and Materials, State Key Laboratory of Hydrology–Water Resources and Hydraulic Engineering , Hohai University , Nanjing , Jiangsu 210098 , PR China
4. Institute of Space Sciences , Magurele–Bucharest , Romania