Text and Data Mining valid from 2014-11-24
Received: 11 July 2014
Revised: 29 September 2014
Accepted: 10 October 2014
First Online: 24 November 2014
Change Date: 20 August 2015
Change Type: Correction
Change Details: This article has been corrected since Advance Online Publication and a corrigendum is also printed in this issue.
: The authors declare no conflict of interest.