Text and Data Mining valid from 2019-11-04
Received: 8 May 2019
Accepted: 26 September 2019
First Online: 4 November 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.