Wang, Haijiang
Pan, Lili
Deng, Wenxiu
Yang, Guangjie
Liu, Xikui
Article History
Received: 31 August 2015
Revised: 28 December 2015
Accepted: 5 January 2016
First Online: 2 March 2016
Competing interests
: The authors declare no conflict of interest.
Free to read: This content has been made available to all.