Text and Data Mining valid from 2018-10-08
Received: 16 August 2018
Accepted: 24 September 2018
First Online: 8 October 2018
Compliance with Ethical Standards
: Authors declare that they have no conflict of interest.
: This article does not contain any studies which experiments with human participants or animals and all institutional and international ethical standards have been followed.
: Informed consent was obtained from all individual participants included in the study.