https://www.tandfonline.com/doi/pdf/10.1080/13501763.2022.2036791?needAccess=true
https://www.brookings.edu/wp-content/uploads/2021/06/Moving-Up.pdf
https://www.economiesuisse.ch/de/artikel/immerhin-zugang-zu-arbeitskraeften-aus-drittstaaten-gesichert
https://www.hamiltonproject.org/assets/files/UnionsEA_Web_8.19.pdf