https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef22029en.pdf
https://www.socialeurope.eu/five-theses-for-a-new-left
http://www.progressives-zentrum.org/wp-content/uploads/2018/10/Les-Oubliés-Entretiens-sur-les-terres-où-prospère-le-vote-extrême_Das-Progressive-Zentrum_Johannes-Hillje.pdf
https://www.ecfr.eu/article/commentary_european_solidarity_tracker_the_solidarity_that_always_was_there