https://ecipe.org/blog/trade-relationship-status-open/?mc_cid=88a1251206&mc_eid=286ad5ef5f
http://sro.sussex.ac.uk/id/eprint/110932/1/BP-70.pdf
https://www.wto.org/english/res_e/booksp_e/oneyukr_e.pdf
https://www.eda.admin.ch/dam/dea/fr/documents/folien/Folien-Abkommen_fr.pdf