Funding for this research was provided by:
National Science Foundation (OCE-0451790)
Austrian Science Fund (P29678-N28)
Text and Data Mining valid from 2018-10-17
Received: 27 March 2018
Accepted: 27 September 2018
First Online: 17 October 2018
: The authors declare that they have no competing interest.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.