Wang, Hongru
Feng, Liang
Zheng, Huan
Zeng, Yibin
Liu, Bin
Article History
Received: 31 January 2020
Revised: 29 March 2020
Accepted: 29 April 2020
First Online: 11 May 2020
Competing interests
: The authors declare no competing interests.
: Written informed consents were provided by parents or children (whose age was more than 8 years old) before information was collected.