http://spinelligroup.eu/sites/spinelli/files/2018_manifesto_en.pdf
https://www.cdu.de/system/tdf/media/dokumente/ergebnis_sondierung_cdu_csu_spd_120118_2.pdf?file=1&type=field_collection_item&id=12434
https://www.europarl.europa.eu/at-your-service/files/be-heard/eurobarometer/2019/parlemeter-2019/executive-summary/en-parlemeter-2019-executive-summary.pdf
https://www.esri.ie/system/files/publications/SUSTAT106_1.pdf