1. Department of Mathematics and Statistics, Central University of Punjab, Bathinda 151401, India
2. Department of Mathematics and Sciences, Prince Sultan University, P. O. Box 66833, Riyadh 11586, Saudi Arabia
3. Department of Medical Research, China Medical University, Taichung 40402, Taiwan
4. Department of Mathematics, Kyung Hee University, Kyungheedae-ro 26, Dongdaemun-gu, Seoul 02447, Korea