https://open.overheid.nl/documenten/ronl-48b77cf7bdf0f91d4ed394ca2a37d2041bc50647/pdf
http://www.niesr.ac.uk/sites/default/files/publications/NIESR%20GE%20Briefing%20Paper%20No.%204%20-%20Agriculture%20in%20the%20UK_0.pdf
https://blogs.lse.ac.uk/brexit/2019/12/03/a-missed-opportunity-revisiting-the-euro-referendum-that-never-was-from-a-historical-perspective/
https://www.suerf.org/docx/f_ec43638b66e16a5bbede9b710b12b0c7_32333_suerf.pdf