Zyriax, Birgit-Christiane http://orcid.org/0000-0002-5377-5956
Vettorazzi, Eik http://orcid.org/0000-0002-3737-6402
Hamuda, Ahmad
Windler, Eberhard
Article History
Received: 20 November 2017
Revised: 4 January 2018
Accepted: 5 January 2018
First Online: 2 March 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.