1. Alvarez, O., Eizagirre, X., Flores, A., Grande, N., Hidalgo, E., Inarra, I., Lauzirika, J. and Portugal, T. 2015. The Unification of the Basque Language. Euskaliak. http://euskalkiak.eus/en/euskararen_batasuna.php
2. Bengtson, J. D. 2017. The Anthropological Context of Euskaro-Caucasian. Iran and the Causus. 21(1). Brill.
3. Bérces, K. B. and Ulfsbjorninn, S. 2022. Cross-morphemic palatalization in Getxo Basque: empty positions, bipositionality, and place licensing. The Linguistic Review. De Gruyter Mouton.
4. Crowley, T. and Bowern, C. 2010. An Introduction to Historical Linguistics. 4th edition. Oxford University Press.
5. Corum, C. 1972. Palatalization Phenomena in Basque. ASJU.