1. Department of Mathematics, Kuztown University of Pennsylvania, 15200 Kutztown Road, Kuztown, PA-19530, USA
2. School of Mathematics, University of the Witwatersrand, Wits 2050, Johannesburg, South Africa
3. Centre for Mathematics and Statistics, Central University of Punjab, Bathinda-151001, Punjab, India
4. Department of Mathematics and Statistics, Sultan Qaboos University, P.O. Box 36, Al Khod 123, Muscat, Sultanate of Oman
5. Operator Theory and Applications Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box-80203, Jeddah-21589, Saudi Arabia
6. Department of Mathematics and Statistics, Tshwane University of Technology, Pretoria-0008, South Africa
7. School of Electronics and Information Engineering, Wuhan Donghu University, Wuhan, 430212, PR China