
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650455/customs_bill_white_paper_print.pdf

http://blogs.lse.ac.uk/brexit/2017/07/06/the-1bn-bung-wont-protect-northern-ireland-from-the-pain-of-a-hard-brexit/

https://blogs.lse.ac.uk/brexit/2020/02/26/long-read-from-anglo-irish-to-british-irish-relations-whats-next/