Funding for this research was provided by:
Universität Potsdam (none)
Text and Data Mining valid from 2019-12-01
Received: 1 August 2019
Accepted: 6 December 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: Not applicable.
: The author agrees to publish.
: The author declares that he has no competing interests.