Tref bost: Gwahaniaeth rhwng fersiynau

Mae'r Post Brenhinol yn nodi bod rhaid i'r dref bost gael ei gynnwys ar bob eitem a dylai gael eu ysgrifennu mewn llythrennau bras.<ref>[{{Cite web |url=http://www.royalmail.com/portal/rm/content1?catId=400044&mediaId=32700664 |title=Post Brenhinol Cyngor Post - Help a chyngor ar gyfer anfon eitemau (Saesneg)] |access-date=2011-07-13 |archive-date=2011-06-08 |archive-url=https://web.archive.org/web/20110608090438/http://www.royalmail.com/portal/rm/content1?catId=400044&mediaId=32700664 |url-status=dead }}</ref>

*[http://www.evoxfacilities.co.uk/evoxptn.html Rhestr o drefi bost yn y DU] {{Webarchive|url=https://web.archive.org/web/20120219123813/http://www.evoxfacilities.co.uk/evoxptn.html |date=2012-02-19 }} (yn 2007)