R.I.A. Proceedings of the Royal Irish Academy, Archæology, Linguistic and Literature. References to volumes according to the consecutive numbering.
R.I.A. Trans. Transactions of the Royal Irish Academy.
R.Q.H. Revue des Questions Historiques.
R.T.A. Register of the Abbey of St. Thomas, Dublin, ed. J. T. Gilbert (R.S.), 1889.
Reeves. W. Reeves, Ecclesiastical Antiquities of Down, Connor and Dromore, 1847.
Reeves, Churches. W. Reeves, Ancient Churches of Armagh, 1860.
Richard of Hexham. Historia Ricardi prioris Haugustaldensis, in Chronicles of Stephen, etc., ed. Howlett (R.S.), iii. (1886), 137 ff.
Theiner. A. Theiner, Vetera Monumenta Hibernorum et Scotorum, 1216-1547, Romae, 1864.
Todd. J. H. Todd, St. Patrick Apostle of Ireland, 1864.