Text and Data Mining valid from 2016-01-29
Received: 8 July 2015
Accepted: 15 December 2015
First Online: 29 January 2016
Change Date: 20 May 2016
Change Type: Update
Change Details: A correction has been published and is appended to both the HTML and PDF versions of this paper. The error has not been fixed in the paper.
: The authors declare no competing financial interests.