Funding for this research was provided by:
Shanghai University of Finance and Economics Innovation Fund for Graduate Student (CXJJ-2017-425)
The Fundamental Research Funds of Shandong University (2018GN050)
Projects of National Social Science Fund of China (19BTJ032)
Article History
Received: 8 May 2019
First Online: 17 August 2019
Compliance with ethical standards
:
: On behalf of all authors, the corresponding author states that there is no conflict of interest.