Text and Data Mining valid from 2018-05-03
Received: 1 November 2017
Accepted: 27 March 2018
First Online: 3 May 2018
Change Date: 17 May 2019
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.