Richard Cable: BBC Knowledge & Learning | The union jack: A very complex flag. In: BBC News. 10.Januar 2013 (bbc.co.uk[abgerufen am 19.Juni 2021]): „According to the Flag Institute, a leading research centre that manages the United Kingdom Flag Registry, it is a "relatively recent idea" that the flag is only a jack when flown from a warship.“
Richard Cable:BBC Knowledge & Learning | The union jack: A very complex flag. In: BBC News. 10.Januar 2013 (bbc.co.uk[abgerufen am 19.Juni 2021]).
Union Flag: approved designs.In:College of Arms.Abgerufen am 18.Dezember 2021(britisches Englisch):„For the avoidance of doubt and the sake of convenience, Garter King of Arms, under the authority of the Earl Marshal, has approved two versions of the Union flag as being accurate representations suitable for use. These are of the proportions 5:3, commonly flown on land; and 2:1, commonly flown at sea.“
Royal Union Flag.In:Canadian Heritage / Patrimoine canadien.ArchiviertvomOriginal(nicht mehr online verfügbar)am13.April 2008;abgerufen am 19.August 2011(englisch).
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„The cross of St George ... was combined with the cross of St Andrew in 1606. ...
The cross saltire of St Patrick ... was combined with the previous Union Flag of St George and St Andrew, after the Act of Union of Ireland with England (and Wales) and Scotland on 1 January 1801, to create the Union Flag that has been flown ever since.“
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„The cross of St George, patron saint of England since the 1270's, is a red cross on a white ground.
The cross saltire of St Andrew, patron saint of Scotland, is a diagonal white cross on a blue ground.
The cross saltire of St Patrick, patron saint of Ireland, is a diagonal red cross on a white ground.“
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„After James I succeeded to the throne, it was combined with the cross of St Andrew in 1606“
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„The term 'Union Jack' possibly dates from Queen Anne's time (r. 1702–14), but its origin is uncertain.“
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„It may come from the 'jack-et' of the English or Scottish soldiers, or from the name of James I who originated the first union in 1603.“
Union Jack.In:The official website of The British Monarchy.Royal Household,15.Januar 2016,abgerufen am 19.Juni 2021(englisch):„Another alternative is that the name may be derived from a proclamation by Charles II that the Union Flag should be flown only by ships of the Royal Navy as a jack, a small flag at the bowsprit; the term 'jack' once meant small.“
Royal Union Flag.In:Canadian Heritage / Patrimoine canadien.ArchiviertvomOriginal(nicht mehr online verfügbar)am13.April 2008;abgerufen am 19.August 2011(englisch).
