https://publications.parliament.uk/pa/ld201719/ldselect/ldconst/69/69.pdf
http://europa.eu/rapid/press-release_MEMO-17-2001_en.htm
https://ec.europa.eu/commission/sites/beta-political/files/joint_report.pdf
https://www.spiegel.de/politik/ausland/brexit-deutscher-ex-botschafter-warnt-vor-zu-selbstgefaelligem-blick-auf-grossbritannien-a-0e50fbd5-de82-4b1a-b7cc-eef28f56577c