http://fedtrust.co.uk/views-from-the-federal-trust/free-movement-and-migration/
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/655232/DExEU_ARA_v5.0_amended_version_14.08.17__1_.pdf
https://www.gov.uk/government/news/david-davis-teesport-speech-implementation-period-a-bridge-to-the-future-partnership-between-the-uk-eu
https://www.instituteforgovernment.org.uk/sites/default/files/publications/negotiating-brexit-preparing-talks-uk-future-relationship-eu-FINAL_1.pdf