Guan, H https://orcid.org/0000-0002-4683-601X
Tan, P
Xie, L
Mi, B
Fang, Z
Li, J
Yue, J
Liao, H
Li, F
Article History
Received: 19 April 2015
Revised: 30 June 2015
Accepted: 25 July 2015
First Online: 7 September 2015
Competing interests
: The authors declare no conflict of interest.