Text and Data Mining valid from 2018-10-04
Received: 17 May 2018
Revised: 24 August 2018
Accepted: 29 September 2018
First Online: 4 October 2018
Compliance with ethical standards
: The authors have no conflict of interest to declare.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: Informed consent was obtained from all authors included in the study.