1. Department of Mathematics, C.C.S. University, Meerut-250004, India
2. Department of Mathematics, School of Advanced Sciences, Vellore Institute of Technology (VIT) University, Vellore 632014, Tamil Nadu, India
3. Department of Mathematics, Indira Gandhi National Tribal University, Lalpur, Amarkantak, Anuppur, Madhya Pradesh 484 887, India
4. Department of Mathematics, MIT Campus, T.U, Janakpurdham, Nepal
5. Department of Mathematics, Rajarshi Janak Campus, T.U, Janakpurdham 45600, Nepal