Zhao, L-G
Sun, J-W
Yang, Y
Ma, X
Wang, Y-Y
Xiang, Y-B
Text and Data Mining valid from 2015-05-13
Version of Record valid from 2015-05-13
Article History
Received: 15 August 2014
Revised: 16 March 2015
Accepted: 6 April 2015
First Online: 13 May 2015
Competing interests
: The authors declare no conflict of interest.
Free to read: This content has been made available to all.