Text and Data Mining valid from 2018-07-13
Received: 27 February 2018
Revised: 4 May 2018
Accepted: 3 June 2018
First Online: 13 July 2018
Change Date: 7 October 2019
Change Type: Correction
Change Details: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Compliance with ethical standards
: The authors declare that they have no conflict of interest.