Ceiltigh agus Normannaigh /
Mac Gearailt, Gearóid.
Ó Néill, Mı́cheál.
Baile Átha Cliath [i.e. Dublin] Oifig an tSoláthair (Stationery Office)
1978
Originally published as: Celts and Normans, Dublin: Gill and Macmillan, 1969