Xia, Hui http://orcid.org/0000-0002-2517-2410
Wan, Yunhai
Assenmacher, Wilfried
Mader, Werner
Yuan, Guoliang
Lu, Li
Article History
Received: 6 May 2014
Revised: 11 July 2014
Accepted: 15 July 2014
First Online: 19 September 2014
Competing interests
: The authors declare no conflict of interest.