Li, S
Li, L
Zhu, Y
Huang, C
Qin, Y
Liu, H
Ren-Heidenreich, L
Shi, B
Ren, H
Chu, X
Kang, J
Wang, W
Xu, J
Tang, K
Yang, H
Zheng, Y
He, J
Yu, G
Liang, N
Article History
Received: 20 November 2013
Revised: 14 March 2014
Accepted: 22 March 2014
First Online: 17 April 2014
Competing interests
: The authors declare no conflict of interest.