1. GPC Online. 2014. Aberystwyth: University of Wales Centre for Advanced Welsh & Celtic Studies. Available at http://www.wales.ac.uk/dictionary (last accessed 09.08.2019).
2. Mayhoff, K. F. T. (ed.). 1906. Naturalis Historia. Leipzig: Teubner. Available at http://data.perseus.org/texts/urn:cts:latinLit:phi0978.phi001 (last accessed 25.08.2019).
3. Bergin, O. & Best, R. I. (eds & trans.). 1937. The Wooing of Étaín. In CELT: Corpus of Electronic Texts, ed. B. Hazard. Cork: University College, Cork. Avilable at https://celt.ucc.ie/published/T300012/index.html (last accessed 13.03.2017).
4. Biblia Sacra Vulgata (English standard version). 2007. Stuttgart: Deutsche Bibelgesellschaft. Available at http://www.bibelwissenschaft.de (last accessed 25.08.2019).