https://wiiw.ac.at/regulatory-convergence-within-technical-barriers-to-trade-dlp-6630.pdf
http://ecdpm.org/wp-content/uploads/ETTG-Brief-Keijzer-Medinilla-November-2017.pdf
https://uk.reuters.com/article/uk-britain-eu-options/stairway-to-brexit-barnier-maps-out-uks-canadian-path-idUKKBN1ED23R
https://www.wto.org/english/res_e/reser_e/ullbergpresentation_e.pdf