https://ec.europa.eu/commission/sites/beta-political/files/position-paper-public-procurement_en.pdf
https://ec.europa.eu/commission/sites/beta-political/files/police_judicial_cooperation_in_criminal_matters_0.pdf
https://www.ifs.org.uk/publications/10302
http://www.voxeurop.eu/en/2017/eu-uk-relations-5120821