http://bruegel.org/wp-content/uploads/2017/03/WP_2017_03-.pdf
https://ec.europa.eu/commission/sites/beta-political/files/aviation.pdf
https://publications.parliament.uk/pa/cm201719/cmselect/cmworpen/848/848.pdf
https://blogs.lse.ac.uk/brexit/2020/02/26/long-read-from-anglo-irish-to-british-irish-relations-whats-next/