1. Department of Statistics, Quaid-i-Azam University, Islamabad, Pakistan
2. Department of Chemistry, COMSATS University Islamabad, Islamabad, Pakistan
3. Department of Mathematics, College of Sciences and Arts (Muhyil), King Khalid University, Muhyil, Saudi Arabia
4. Department of Mathematics and Computer, College of Sciences, Ibb University, Ibb, Yemen
5. Department of Mathematics, College of Science and Humanities in Al-Aflaj, Prince Sattam Bin Abdulaziz University, Al-Aflaj, Saudi Arabia
6. Administration Department, Administrative Science College, Thamar University, Thamar, Yemen