1. University of Aden, Department of Mathematics, Aden, Yemen
2. University of Jordan, Department of Mathematics, Amman, Jordan
3. Université de Sousse, Institut Supérieur d’Informatique et des Techniques de Communication, Hammam Sousse 4000, Sousse, Tunisia
4. China Medical University Hospital, China Medical University, Taichung 40402, Taiwan
5. Department of Mathematics and Applied Mathematics, Sefako Makgatho Health Sciences University, Ga-Rankuwa, South Africa