https://www.boe.es/boe/dias/2021/12/30/pdfs/BOE-A-2021-21788.pdf
https://www.wired.com/story/russian-techies-exodus-ukraine/?utm_source=newsletter&utm_medium=email&utm_campaign=23%2F03%2F22++(Copy)+(Copy)#intcid=_wired-verso-hp-trending_444226e1-5b4d-43c1-bdac-d4a2c5859d2f_popular4-1
https://www.etuc.org/fr/presse/rien-quen-2017-chaque-travailleur-subi-une-perte-de-salaire-de-1764-€-en-raison-de-la#.WqrAWUxuI2x
https://www.publications.parliament.uk/pa/ld201314/ldselect/ldeucom/164/164.pdf