Best, Raymond http://orcid.org/0000-0002-3234-9237
Eberle, Julia
Beck, Florian
Beckmann, Johannes
Becker, Ulrich
Article History
Received: 30 July 2018
Accepted: 29 November 2018
First Online: 19 December 2018
Compliance with ethical standards
: This retrospective survey does not contain any experimental studies on human participants or animals and thus meets all ethical standards described in the Declaration of Helsinki.
: The authors declare that they have no conflicts of interest.