
https://www.nao.org.uk/wp-content/uploads/2017/07/The-Customs-Declaration-Service.pdf

https://corporateeurope.org/power-lobbies/2017/12/big-business-brexit-corporate-interests-still-dominate-brexit-and-trade

http://www.cesifo-group.de/ifoHome/publications/working-papers/CESifoWP/CESifoWPdetails?wp_num=6430&CESifoWP.search=+