Text and Data Mining valid from 2018-02-28
Received: 28 December 2017
Accepted: 3 February 2018
First Online: 28 February 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with participants or animals performed by any of the authors.
: There were no participants in this publication; therefore, informed consent was not obtained.