Li, Ning
Chen, Yun-Ru
Ding, Zehong
Li, Pinghua
Wu, Ying
Zhang, Ai
Yu, Sheng
Giovannoni, James J.
Fei, Zhangjun
Zhang, Wei
Xiang, Jenny Z.
Xu, Chunming
Liu, Bao
Zhong, Silin
Article History
Received: 10 September 2014
Accepted: 24 December 2014
First Online: 26 January 2015
Competing interests
: The authors declare no competing financial interests.