http://www.ecfr.eu/page/-/ECFR_215_GERMANY_VOTES_EUROPEAN_DILEMMAS_IN_THE_FEDERAL_ELECTION.pdf
http://foroparalaconcordiacivil.com/carta-sobre-situacion-en-espana-y-cataluna/
https://www.tandfonline.com/doi/epdf/10.1080/01402382.2023.2168945?needAccess=true&role=button