Best, R. I., Bibliography of Irish Philology and Irish Printed Literature, Dublin, 1913.

Boswell, An Irish Precursor of Dante, London, 1908.

Brash, Ogam-inscribed Monuments of the Gaedhil, London, 1899.

Brooks, Stopford, History of English Literature from the Beginning to the Norman Conquest, London.

Bury, J. B., The Life of St. Patrick and his Place in History, London, 1905.

Cambridge History of English Literature, vol. i, Chaps. xii, xvi.

Catholic Encyclopedia, 15 vols., New York, 1907.

Concannon, (Mrs.) Helen, Life of St. Columban, A Study of Ancient Irish Monastic Life, Dublin, 1915.

Coffey, George, New Grange and other Incised Monuments, Dublin, 1912.

Coffey, George, The Bronze Age in Ireland, Dublin, 1913.