https://wiiw.ac.at/the-emissions-reduction-potential-for-freight-transport-on-a-high-speed-rail-line-along-the-european-silk-road-dlp-6635.pdf
https://giwps.georgetown.edu/wp-content/uploads/2019/12/WPS-Index-2019-20-Report.pdf
https://dserver.bundestag.de/btd/20/057/2005700.pdf