Shao, Liangshan
Zhao, Shuoqiang http://orcid.org/0000-0002-6295-3144
Article History
Received: 27 March 2018
Revised: 15 May 2018
Accepted: 17 May 2018
First Online: 6 July 2018
Compliance with Ethical Standards
:
: This article does not contain any studies with human participants or animals performed by any of the authors. In this study, we did not collect any samples of human and animals. All the data used in this article are from the National Bureau of Statistics of the People’s Republic of China, which are publicly available as a book.
: The authors declare that they have no conflict of interest.