
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/662744/State_of_the_Nation_2017_-_Social_Mobility_in_Great_Britain.pdf

https://apnews.com/article/prison-to-plate-inmate-labor-investigation-c6f0eb4747963283316e494eadf08c4e

https://www.zi-mannheim.de/fileadmin/user_upload/downloads/forschung/forschungsverbuende/MHG-Studie-Endbericht-Zusammenfassung.pdf