1. Department of Engineering Mathematics, College of Engineering, Koneru Lakshmaiah Education Foundation, Vaddeswaram 522302, Andhra Pradesh, India
2. School of Mathematical Sciences, Zhejiang Normal University, Jinhua 321004, China
3. Mathematics Department of Humanities College, Zhejiang Guangsha Vocational and Technical University of Construction, Jinhua 321004, China
4. Department of Mathematics, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India