1. Department of Statistics, Quaid-i-Azam University, Islamabad, Pakistan
2. Federal Urdu University, Arts, Sciences and Technology, Islamabad, Pakistan
3. Department of Mathematics, College of Sciences and Arts (Muhyil), King Khalid University, Muhyil 61421, Saudi Arabia
4. Department of Civil, Environmental and Natural Resources Engineering, Lulea University of Technology, 971 87 Lulea, Sweden
5. Mathematics Department, College of Humanities and Science, Prince Sattam Bin Abdulaziz University, Al Aflaj, Saudi Arabia
6. Administration Department, Administrative Science College, Thamar University, Thamar, Yemen