3Graves, Robert. The White Goddess: a Historical Grammar of Poetic Myth. New York: Farrar, Straus and Giroux, 1966. 93.
In a 1909 journal article, Mary Hobson, writing about a souterrain in Northern Ireland states, "The building of them is nearly always attributed to the 'Danes,' the 'Fairies,' the 'Good People,' or in rare instances to the Picts. The Danes here referred to are not the modern Danes, but probably the Tuatha-da-Danaan, a people who are said to have lived in Ireland before the coming of the Celts." (Hobson, Mary. "Some Ulster Souterrains." The Journal of the Royal Anthropological Institute of Great Britain and Ireland 39.January-June (1909): 226-27.)