Funding for this research was provided by:
Bundesministerium für Bildung und Forschung (not applicable)
Text and Data Mining valid from 2019-09-12
Received: 25 April 2019
Accepted: 7 June 2019
First Online: 12 September 2019
Ethics approval and consent to participate
: Approval by the ethics committee of the University of Heidelberg, AFmu-106/2006, was obtained. All subjects gave written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.