
http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:52016DC0950&from=en

http://www.diw.de/documents/publikationen/73/diw_01.c.562050.de/17-29.pdf

https://centreonconstitutionalchange.ac.uk/sites/default/files/2021-04/Union%20at%20the%20Crossroads.pdf