Article History
Received: 23 January 2018
Accepted: 20 April 2018
First Online: 27 April 2018
Ethics approval and consent to participate
: Ethical approval for this research study was obtained from the University of Luebeck in June 2016 (Approval No. 16–123). Participation in the study was voluntary. No additional data were evaluated. Written informed consent was obtained from each participant.
: The authors declare that they have no competing interests.
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