1. Department of Mathematics, Institute of Science, Banaras Hindu University, Varanasi, India
2. Department of Mathematics, Butwal Multiple Campus, T.U., Butwal, Lumbini, Nepal
3. School of Mathematics, Thapar Institute of Engineering & Technology, Patiala, India
4. Department of Basic Science and Humanities, Indian Institute of Information Technology, Bhagalpur, India
5. Department of Mathematics, University of Florida, Gainesville, FL, USA