School of Management, Lanzhou University, Lanzhou730000, China
School of Management, Lanzhou University, Lanzhou730000, China/School of Economics and Finance, Xi,an Jiaotong University, Xi,an710061, China
Copyright © Zhikun Du, Guorong Chai et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.