https://www.esri.ie/system/files/publications/SUSTAT106_1.pdf
http://foroparalaconcordiacivil.com/carta-sobre-situacion-en-espana-y-cataluna/
https://www.opendemocracy.net/can-europe-make-it/andreas-rahmatian/eu-as-britain-s-constitutional-stabiliser?utm_source=Daily+Newsletter&utm_campaign=8d26251e8d-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-8d26251e8d-407405485
https://www.socialeurope.eu/2017/07/for-social-europe/