https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf
https://blogs.sussex.ac.uk/uktpo/2017/06/12/animal-welfare-and-post-brexit-trade/
https://publications.parliament.uk/pa/bills/cbill/2019-2020/0007/20007.pdf
https://www.opendemocracy.net/en/opendemocracyuk/customs-union-leaves-everything-play-trade-justice/?utm_source=Daily+Newsletter&utm_campaign=f531c721c4-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-f531c721c4-407405485