Herrig, Ilona
Seis, Wolfgang
Fischer, Helmut
Regnery, Julia
Manz, Werner
Reifferscheid, Georg
Böer, Simone
Funding for this research was provided by:
Bundesministerium für Bildung und Forschung (02WRS1278A)
Bundesministerium für Verkehr und Digitale Infrastruktur
Article History
Received: 24 May 2019
Accepted: 22 August 2019
First Online: 23 September 2019
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.