
https://ec.europa.eu/commission/sites/beta-political/files/financial-settlement-essential-principles-draft-position-paper_en.pdf

http://www.cer.eu/sites/default/files/bulletin_118_js-sl_article2.pdf

https://www.gov.uk/government/speeches/pm-commons-statement-on-eu-reform-and-referendum-22-february-2016