https://theconversation.com/eu-enlargement-what-does-the-future-hold-227716
http://www.tilisone.net/wp-content/uploads/2017/10/APuZ_2017-38-39_online-1.pdf
https://www.opendemocracy.net/can-europe-make-it/patrice-de-beer/catalonia-now-what?utm_source=Daily+Newsletter&utm_campaign=0b1fe93b93-DAILY_NEWSLETTER_MAILCHIMP&utm_medium=email&utm_term=0_717bc5d86d-0b1fe93b93-407405485
http://upceo.ceo.gencat.cat/wsceop/6508/Resumen%20en%20espa%C3%B1ol%20-874.pdf