References for Tewdr (Tudor) of Penmynedd
D.Schwennicke:
Europäische Stammtafeln, Vol. III/1, Tafel 158.
Marburg, 1984
A.M.Stokvis:
Manuel d'histoire.
Amsterdam, 1966
A.Taute:
The Kings and Queens of Great Britain.
London, 1970