1. Lorestan University, Faculty of Science, LorestanKhoramabad, Iran;
2. Indiana University, Fort Wayne, INUSA;
3. Department of Mathematical Sciences, Purdue University Fort Wayne, Fort Wayne, IN46805, USA;
4. Department of Mathematics, College of Sciences, Shiraz University, Shiraz, 71457-44776, Iran;
5. Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran;
6. School of Computer Science, University of Oklahoma, Norman, USA;
7. Department of Mathematics, Yazd University, Yazd, 89175–741, Iran;
8. Institute of Applied Mathematics and Information Science University of Qiongzhou, SanyaHainan, 572022, PR China;