1. Department of Mathematics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore-641 020, Tamilnadu, India
2. Department of Mathematics, Cankaya University, Ankara, 06530, Turkey
3. Institute of Space Sciences, Magurele-Bucharest, Romania
4. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan