Funding for this research was provided by:
Key Project in Science and Technology Agency of Henan Province (182102110473)
Innovation and Entrepreneurship Training Program, Henan University (201810475069)
Text and Data Mining valid from 2019-07-09
Received: 21 December 2018
Accepted: 29 June 2019
First Online: 9 July 2019
: The authors declare that they have no competing interests.