Wright, Neil. The Historia Regum Britannie of Geoffrey of Monmouth (англ.). — Woodbridge, England: Boydell and Brewer[англ.], 1984. — P. xvii—xviii. — ISBN 978-0-85991-641-7.. — «This fusion of heterogeneous sources, which is apparent almost everywhere in the Historia, completely dispels the fiction that the work is no more than a translation of a single Breton (or Welsh) book».