Han, S
Wang, B
Jin, W
Xiao, Z
Chen, B
Xiao, H
Ding, W
Cao, J
Ma, F
Li, X
Yuan, B
Zhu, T
Hou, X
Wang, J
Kong, J
Liang, W
Dai, J
Article History
Received: 5 January 2014
Revised: 10 August 2014
Accepted: 6 September 2014
First Online: 14 October 2014
Competing interests
: The authors declare no conflict of interest.