Text and Data Mining valid from 2020-02-06
Received: 13 November 2019
Accepted: 30 January 2020
First Online: 6 February 2020
Compliance with ethical standards
: All 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.
: This is not a study on human or animal subject and requires no informed consent.