
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1663en.pdf

https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1714en.pdf

https://www.ceps.eu/system/files/CEPS%20-%20LINKEDIN%20study%20FINAL.pdf