Institution: | 1. School of Science, Nantong University, Nantong 226019, China;2. School of Mathematical Sciences, Soochow University, Suzhou 215006, China;1. Beijing International Studies University, School of Economics, Trade and Event Management, 100024 Beijing, China;2. Univ. Bretagne-Sud, CNRS UMR 6205, LMBA, Campus de Tohannic, BP 573, F-56000 Vannes, France |