Text and Data Mining valid from 2018-11-02
Received: 10 May 2018
Revised: 2 September 2018
Accepted: 2 October 2018
First Online: 2 November 2018
Change Date: 31 July 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.