https://www.electoralcommission.org.uk/cy/pwy-ydym-ni-a-beth-rydym-yn-ei-wneud/ein-safbwyntiau-hymchwil/ein-hymchwil/gwerthusiad-cynlluniau-peilot-pleidleisio-ymlaen-llaw
https://www.electoralcommission.org.uk/who-we-are-and-what-we-do/our-views-and-research/our-research/advance-voting-pilots-evaluation