Gai, Ying-Ping
Li, Yi-Qun
Guo, Fang-Yue
Yuan, Chuan-Zhong
Mo, Yao-Yao
Zhang, Hua-Liang
Wang, Hong
Ji, Xian-Ling
Article History
Received: 26 February 2014
Accepted: 2 June 2014
First Online: 20 June 2014
Competing interests
: The authors declare no competing financial interests.