Text and Data Mining valid from 2018-12-05
Received: 17 October 2018
Accepted: 27 November 2018
First Online: 5 December 2018
Compliance with ethical standards
: None of the authors has any conflict of interest to disclose.
: This article does not contain any studies with human or animal subjects performed by any of the authors.
: For this type of study formal consent is not required.