Additional sources Edward Twining (Lord Twining), A History of the Crown Jewels of Europe, London: B.T. Batsford, 1960.
Abgerufen am 13. Dezember 2016.  Zusätzliche Quellen Edward Twining (Lord Twining), A History of the Crown Jewels of Europe, London: B.T. Batsford, 1960.