Text and Data Mining valid from 2018-07-12
Received: 21 February 2018
Accepted: 28 June 2018
First Online: 12 July 2018
Change Date: 20 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 been fixed in the paper.
: The authors declare no competing interests.