http://trade.ec.europa.eu/doclib/docs/2018/october/tradoc_157468.pdf
http://www.iata.org/publications/economic-briefings/value-of-air-cargo-2016-summary.pdf
https://www.brookings.edu/articles/getting-china-right-resoluteness-without-overreaction/
https://www.niesr.ac.uk/sites/default/files/publications/NIESR%20Landscape%20Series%20-%20China%20and%20the%20United%20Kingdom%2C%20Economic%20Relationships_0.pdf