Text and Data Mining valid from 2018-09-26
Received: 10 May 2018
Revised: 26 July 2018
Accepted: 2 August 2018
First Online: 26 September 2018
Change Date: 21 November 2018
Change Type: Correction
Change Details: This article was originally published under standard licence, but has now been made available under a CC BY 4.0 license. The PDF and HTML versions of the paper have been modified accordingly.
Compliance with ethical standards
: The authors declare that they have no conflict of interest.