1. Department of Mathematics, COMSATS University Islamabad, Islamabad Campus, Islamabad 45550, Pakistan
2. Department of Architecture, Federico II Naples University, Via Toledo 402, 80134 Naples, Italy
3. Department of Mathematics, College of Sciences, King Khalid University, Abha 61413, Saudi Arabia
4. Department of Mathematics, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia