Funding for this research was provided by:
Bundesministerium für Bildung und Forschung (01UT1422C)
Text and Data Mining valid from 2019-02-01
Received: 18 December 2017
Accepted: 22 January 2019
First Online: 1 February 2019
Conflict of interest
: M. Kühnen, S. Silva, J. Beckmann, U. Eberle, R. Hahn, C. Hermann, S. Schaltegger and M. Schmid declare that there is no conflict of interest.