https://www.wto.org/english/res_e/booksp_e/anrep_e/ar23_e.pdf
https://insightcrime.org/investigations/synthetic-silk-road-tracing-china-grey-market-precursor-chemical-trade/
https://ukandeu.ac.uk/wp-content/uploads/2021/11/Brexit-and-Services-Trade-Working-Paper.pdf
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32019R0452&from=EN