1. MCS, National University of Sciences and Technology, Islamabad 44000, Pakistan
2. Department of Mathematics and Statistics, The University of Lahore, Lahore 54000, Pakistan
3. Department of Quantitative Methods, College of Business Administration, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 34212, Saudi Arabia
4. Department of Mathematics and Statistics, Padmakanya Campus, Tribhuvan University, Kirtipur, Nepal