1. Department of Mathematics; Texas A&M University-Kingville; Kingsville TX USA
2. Constantin Brancusi University; Republicii 1 210152 Targu-Jiu Romania
3. School of Mathematics; Statistics and Applied Mathematics, National University of Ireland; Galway Ireland
4. University of Swat; Khyber Pakhtunkhwa Pakistan
5. Abdus Salam School of Mathematical Sciences; GC University Lahore; Lahore 54000 Pakistan