1. Industrial Engineering and Operations Research Department, Columbia University, 500 W. 120th Street, New York, NY 10027, USA
2. Department of Mathematics, Quaid-i-Azam University, Islamabad 45320, Pakistan
3. Department of Mathematics and Statistics, Faculty of Science and Technology, Thammasat University Rangsit Center, Pathum Thani 12120, Thailand
4. Department of Mathematics, Faculty of Science, Islamic University of Madinah, Madinah 42351, Saudi Arabia