Text and Data Mining valid from 2018-02-14
Received: 13 June 2017
Revised: 19 July 2017
Accepted: 20 July 2017
First Online: 14 February 2018
Compliance with ethical standards
: This article does not contain any studies with human participants or animals performed by any of the authors.
: Author declares no conflict of interests in the past 36 months.