https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef18037en.pdf
https://opportunityinsights.org/wp-content/uploads/2020/05/tracker_paper.pdf
https://www.socialeurope.eu/2017/06/strange-non-death-almps/
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/662744/State_of_the_Nation_2017_-_Social_Mobility_in_Great_Britain.pdf