Affiliation: | 1. School of Mathematics and Statistics, Nanjing University of Information Science and Technology, Nanjing 210044, China;2. Department of Mathematics, Swinburne University of Technology, Hawthorn VIC 3122, Australia;1. College of Mathematics and Information Science, Hebei Normal University, Shijiazhuang 050024, PR China;2. Department of Applied Mathematics, Western University, London, Ontario N6A 5B7, Canada |