Knollmann, Martin
Reissner, Volker
Hebebrand, Johannes
Article History
Received: 30 March 2018
Accepted: 19 July 2018
First Online: 24 July 2018
Compliance with ethical standards
:
: This study has been approved by the ethics committee of the University of Duisburg-Essen and has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. All persons gave their informed consent prior to their inclusion in the study.
: The authors declare that they have no conflict of interest.