Text and Data Mining valid from 2019-02-05
Received: 9 December 2018
Accepted: 25 January 2019
First Online: 5 February 2019
Compliance with ethical standards
: This article does not contain any studies with human participants or animals performed by the author. The author declares that this manuscript complies with the ethical rules applicable for this journal.
: The author declares that she has no conflict of interest.