https://www.ipg-journal.de/regionen/asien/artikel/deal-der-superlative-4816/
http://www.iata.org/publications/economic-briefings/value-of-air-cargo-2016-summary.pdf
https://www.wto.org/english/tratop_e/envir_e/trade-climate-change_info_brief_no7_e.pdf
https://www.eca.europa.eu/ECAPublications/SR-2023-13/SR-2023-13_EN.pdf