1. Department of Mathematics, Texas A & M University-Kingsville, Kingsville, TX, USA
2. Department of Mathematical Science, Faculty of Applied Science, Umm Alqura University, Makkah, Saudi Arabia
3. University of Mostaganem, Mostaganem, Algeria
4. Dipartimento di Matematica e Informatica, Università di Catania, Catania, Italy
5. RUDN University, Moscow, Russia