
https://www.cdu.de/system/tdf/media/dokumente/ergebnis_sondierung_cdu_csu_spd_120118_2.pdf?file=1&type=field_collection_item&id=12434

http://www.ips-journal.eu/storage/topics/european-union/article/show/stars-in-their-eyes-2515/

https://www.opendemocracy.net/can-europe-make-it/ashoka-mody/german-social-democrats-have-alienated-their-base-and-fractured-europe?