
https://theconversation.com/why-the-eus-singapore-ruling-does-not-lead-to-a-smoother-brexit-road-for-britain-78116

https://publications.parliament.uk/pa/ld201719/ldselect/ldeucom/129/129.pdf

https://www.sussex.ac.uk/webteam/gateway/file.php?name=briefing-paper-1.pdf&site=18