
https://www.bertelsmann-stiftung.de/de/themen/aktuelle-meldungen/2019/maerz/brexit-kostet-deutschland-bis-zu-zehn-milliarden-euro-jaehrlich/

https://www.theguardian.com/politics/2017/sep/04/uk-trade-deals-after-brexit-theresa-may-eu

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/650455/customs_bill_white_paper_print.pdf