Funding for this research was provided by:
Text and Data Mining valid from 2019-01-03
Received: 9 July 2018
Revised: 5 December 2018
Accepted: 6 December 2018
First Online: 3 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.