Text and Data Mining valid from 2018-07-02
Received: 6 March 2018
Accepted: 15 June 2018
First Online: 2 July 2018
Change Date: 31 July 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 been fixed in the paper.
: The authors declare no competing interests.