
https://www.wto.org/english/res_e/reser_e/ullbergpresentation_e.pdf

https://home.kpmg.com/content/dam/kpmg/nl/pdf/2018/sector/overheid/impact-van-non-tarifaire-handelsbelemmeringen-als-gevolg-van-brexit.pdf

https://ecipe.org/blog/trade-relationship-status-open/?mc_cid=88a1251206&mc_eid=286ad5ef5f