1.
WACEWICZ, Sławomir and ŻYWICZYŃSKI, Przemysław. Beyond protolanguage: Contemporary problems in the evolution of language. Theoria et Historia Scientiarum. Online. 19 December 2012. Vol. 9, pp. 5-12. [Accessed 7 July 2025]. DOI 10.12775/v10235-011-0001-6.