Zhang, Hong
Wang, Huaisong
Yi, Hongping
Zhai, Wenqiang
Wang, Guangzhi
Fu, Qiushi
Article History
Received: 30 December 2015
Revised: 13 March 2016
Accepted: 14 March 2016
First Online: 27 April 2016
Competing interests
: The authors declare no conflict of interest.