Text and Data Mining valid from 2019-01-22
Received: 23 October 2017
Accepted: 2 January 2019
First Online: 22 January 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: For this type of study, formal consent is not required.