Li, Shuxia
Pang, Zengchang
Zhang, Dongfeng
Duan, Haiping
von Bornemann Hjelmborg, Jacob
Tan, Qihua
Kruse, Torben Arvid
Kyvik, Kirsten Ohm
Article History
Received: 27 January 2014
Revised: 14 March 2014
Accepted: 18 March 2014
First Online: 15 May 2014
Competing interests
: The authors declare no conflict of interest.