https://theconversation.com/idea-of-eu-citizenship-still-intangible-for-most-europeans-230994
http://www.ema.europa.eu/docs/en_GB/document_library/Press_release/2017/10/WC500236021.pdf
https://visegradinsight.eu/perfect-storm-covid19-eurosceptic-poland-hungary/
http://www.egmontinstitute.be/content/uploads/2019/03/SPB108.pdf?type=pdf