Funding for this research was provided by:
Deutsche Forschungsgemeinschaft (TH 1288/5-1, SU 187/16-1, LE 645/14-1, SCHM 2664/2-1)
Text and Data Mining valid from 2019-09-19
Received: 29 May 2019
Accepted: 2 September 2019
First Online: 19 September 2019
Compliance with ethical standards
: Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the DFG (Deutsche Forschungsgemeinschaft). All students participated in this study voluntarily but also received a small financial compensation.
: The authors declare that they have no conflicts of interest.