Text and Data Mining valid from 2019-09-10
Received: 19 June 2019
Accepted: 3 September 2019
First Online: 10 September 2019
Compliance with Ethical Standards
: No potential conflicts of interest must be reported.
: Research did not involve human participants or animals.
: Informed consent was obtained from all individual participants included in the study. All the findings, data acquisition and processing in this study comply with the ethical standards laid down in the latest declaration of Helsinki. The study was approved by the local ethics committee of the University of Regensburg (Nr. 16–321-101).