Ó Cróinín (Dáibhí): Early Irish annals from Easter tables: a case restated.
In Peritia 2 (1983), pp. 74–86.
Argues that marginal notes were added to Easter tables in Ireland from the sixth century and that this practise was widespread by the mid-seventh century; the earliest Irish chronicle was compiled from these notes in the mid-eighth century.

Repr. in D. Ó Cróinín, Early Irish history and chronology, pp. 76-86.