
https://www.elysee.fr/admin/upload/default/0001/11/8143fbb609fe8fa002cd7a36deccc1a219766cda.pdf

https://www.eurofound.europa.eu/sites/default/files/ef_publication/field_ef_document/ef1663en.pdf

http://sprc.info/wp-content/uploads/2012/07/Polish-Migrants-in-London-extending-the-stay.pdf