Text and Data Mining valid from 2018-02-28
Received: 15 November 2017
Accepted: 1 February 2018
First Online: 28 February 2018
Change Date: 26 September 2018
Change Type: Correction
Change Details: A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
: The authors declare no competing interests.