https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1710en.pdf
https://www.boe.es/boe/dias/2021/12/30/pdfs/BOE-A-2021-21788.pdf
https://www.boeckler.de/data/downloads/IMK/FMM%20Konferenz%202023/v_2023_10_20_goekten.pdf
https://www.parlament.cat/document/cataleg/48146.pdf