^'If, as is the first criterion of this Encyclopedia, one bases the concept of ‘Celticity’ on language, one can apply the term ‘Celtic’ to ancient Galicia', Koch, John T., ed. (2006). Celtic culture: a historical encyclopedia. ABC-CLIO. pp. 790. ISBN1-85109-440-7.
^Luján Martínez, Eugenio R. (3 May 2006). "The Language(s) of the Callaeci". E-keltoi. 6: The Celts in the Iberian Peninsula: 689–714. Archived from the original on 10 April 2018. Retrieved 21 December 2010.
^' In the northwest of the Iberian Peninsula, and more specifically between the west and north Atlantic coasts and an imaginary line running north–south and linking Oviedo and Mérida, there is a corpus of Latin inscriptions with particular characteristics of its own. This corpus contains some linguistic features that are clearly Celtic and others that in our opinion are not Celtic. The former we shall group, for the moment, under the label northwestern Hispano-Celtic.'Jordán Cólera, Carlos (16 March 2007). "Celtiberian"(PDF). E-keltoi. 6: The Celts in the Iberian Peninsula: 750. Archived from the original(PDF) on 24 June 2011. Retrieved 21 December 2010.