Text and Data Mining valid from 2018-11-03
Received: 19 July 2018
Accepted: 16 October 2018
First Online: 3 November 2018
Compliance with ethical standards
: The authors certify that there is no conflict of interest regarding this manuscript.
: 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.