Tong, Yongdong
Wang, Changming
Funding for this research was provided by:
natural science foundation of Guangxi (No.2018GXNSFAA294094)
Reform and innovation program of degree and postgraduate education in Guangxi university for nationalities (gxun-chxjg201701)
Article History
Received: 12 April 2019
Accepted: 29 August 2019
First Online: 12 September 2019
Ethics approval and consent to participate
: Not applicable.
: The authors declare that they have no competing interests.