1. Department of Mathematics, Allama Iqbal Open University, H-8, Islamabad 44000, Pakistan
2. Section of Mathematics, International Telematic University Uninettuno, Corso Vittorio Emanuele Ⅱ, 39, 00186 Roma, Italy
3. Near East University, Operational Research Center in Healthcare, Nicosia, PC: 99138, TRNC Mersin 10, Turkey
4. Department of Computer Science and Mathematics, Lebanese American University, Beirut, Lebanon
5. Department of Statistics and Operations Research, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia