Funding for this research was provided by:
Ruhr-Universität Bochum
Article History
Received: 2 February 2018
Revised: 28 December 2019
Accepted: 31 December 2019
First Online: 28 January 2020
Interessenkonflikt
: D. Kaya, C. Maier und T. Böhmer geben an, dass kein Interessenkonflikt besteht.