Funding for this research was provided by:
National Natural Science Foundation of China-Yunnan Joint Fund (71771156)
2018 Key Project of the Key Research Institute of Humanities and Social Sciences in Sichuan Province (LYC18-02, DSWL18-2)
Spark Project of Innovation at Sichuan University (2018hhs-43)
Text and Data Mining valid from 2019-10-19
Received: 3 February 2019
Accepted: 4 September 2019
First Online: 19 October 2019
Compliance with Ethical Standards
: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: As this article does not contain any studies with human participants or animals performed by any of the authors, the informed consent is not applicable.