1. Department of Mathematics, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Pakistan
2. Laboratory of Mathematical Analysis and Applications, Faculty of Sciences Dhar Al Mahraz, Sidi Mohamed Ben Abdellah University, Fez, Morocco
3. Department of Mathematics, College of Sciences, King Khalid University, Abha, Saudi Arabia
4. Department of Pediatrics, Yale School of Medicine Yale University, New Haven, CT, USA