1. Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
2. African Institute for Mathematical Sciences, Biriwa, Ghana
3. Division of Mathematics, Stellenbosch University, Western Cape, South Africa
4. Department of Mathematics, University for Development Studies, Navrongo, Ghana
5. Department of Applied Sciences, Guru Kashi University, Bathinda, India
6. Department of Mathematics, Gauhati University, Guwahati 781014, India