Hohendorff, Bernd http://orcid.org/0000-0003-0463-9496
Knappwerth, C.
Franke, J.
Müller, L. P.
Ries, C.
Article History
Received: 25 February 2018
First Online: 30 July 2018
Compliance with ethical standards
:
: All the named authors hereby declare that they have no conflicts of interest to disclose.
: The study was approved by the ethics committee of the university of cologne and followed the most recent version of the Declaration of Helsinki.