Tan, J
Yang, X
Jiang, X
Zhou, J
Li, Z
Lee, P L
Li, B
Robson, P
Yu, Q
Article History
Received: 27 January 2014
Revised: 26 May 2014
Accepted: 27 May 2014
First Online: 17 July 2014
Competing interests
: The authors declare no conflict of interest.