Tolong jelaskan mengenai Sumber dari Elen Luyddog

Morris, Lewis; Evans, Daniel Silvan (1878). Celtic Remains. J. Parker. p. 159. . . . Google Book Search. Retrieved on January 25, 2009. (She is listed as ELEN verch Eudaf.)

Farmer, David Hugh (1997). The Oxford Dictionary of Saints (4th ed). Oxford [u.a.]: Oxford University Press. ISBN 0-19-280058-2. ISBN 978-0-19-280058-9.   (She is listed as Helen of Caernarvon.)

Pennick, Nigel (1997). The Celtic Saints: An Illustrated and Authoritative Guide to These Extraordinary Men and Women. New York: Sterling Pub.; London: Thorsons. ISBN 0-7225-3481-7. ISBN 0-8069-9600-5. ISBN 978-0-7225-3481-6. ISBN 978-0-8069-9600-4. . . . .