
https://www.boeckler.de/pdf/p_study_hbs_376.pdf

https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef22040en.pdf

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/974507/20210331_-_CRED_Report_-_FINAL_-_Web_Accessible.pdf