Text and Data Mining valid from 2018-02-03
Received: 29 November 2017
Accepted: 12 January 2018
First Online: 3 February 2018
Compliance with ethical standards
: Authors declared no personal or financial conflicts 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, formal consent is not required.