1. Department of Mathematics, Allama Iqbal Open University, Islamabad, Pakistan
2. Institut Supérieur d'Informatique et des Techniques de Communication, Université de Sousse, H. Sousse, Tunisia
3. China Medical University Hospital, China Medical University, Taichung, Taiwan
4. Department of Mathematics and Applied Mathematics, Sefako Makgatho Health Sciences University, Ga-Rankuwa, South Africa
5. Department of Mathematics, King Abdulaziz University, Jeddah, Saudi Arabia