Text and Data Mining valid from 2019-07-25
Received: 8 March 2019
Accepted: 11 July 2019
First Online: 25 July 2019
Change Date: 20 August 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.