Text and Data Mining valid from 2019-01-16
Received: 17 September 2018
Accepted: 4 January 2019
First Online: 16 January 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, informed consent is not required.