Corpus of Electronic Texts Edition
An Irish Materia Medica (Author: Tadhg Ó Cuinn)

subsection 17

RIA MS 461 (24 B 2):

A copy made by Joseph Ó Longáin in 1848, stated to have been made from a copy made by Micheál Óg Ó Longáin in 1824, which in turn was made from a copy made by Micheál Ó Longáin in 1761.