https://www.brookings.edu/wp-content/uploads/2022/12/WP82-Hansel-et-al_12.14.pdf
https://www.bwb.gv.at/fileadmin/user_upload/Abschlussbericht_BU_Kraftstoffe_2022_final_barrierefrei.pdf
https://www.bruegel.org/analysis/struggle-cut-emissions-international-aviation-and-shipping