https://theconversation.com/el-espanol-una-lengua-americana-228150
https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef22024en.pdf
http://www.lastampa.it/2016/06/27/italia/politica/rodot-quando-i-referendum-diventano-un-boomerang-JuXpMSRHAkJH5mE0mawMrL/pagina.html
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