Article History
Received: 14 May 2019
Accepted: 4 October 2019
First Online: 6 November 2019
Compliance with ethical guidelines
:
: C. Steinberg, M. Zühlke, T. Bindel, and F. Jenett declare that they have no competing interests.
: The study was conducted in accordance with national law and the recommendations of the German Research Foundation to ensure good scientific practice. The study was officially approved by the Ministry of Rhineland-Palatinate (Germany). The approval of all participants was obtained before the start of the study.