His early works on Dál Riata, the Senchus fer n-Alban and the Iona chronicles which formed part of the later Chronicle of Ireland are contained in his 1974 book Studies in the History of Dalriada.
Os seus primeiros traballos sobre Dál Riata, o Senchus fer n-Alban e as crónicas de Iona, que formaron parte posteriormente da Crónica de Irlanda, están contidos no seu libro de 1974, Studies in the History of Dalriada.