Admiralova, Alexandra N., and Valery V. Beniash-Kryvets. “On Representation Varie Ties of Some HNN-Extensions of Free Groups”. Journal of the Belarusian State University. Mathematics and Informatics, no. 2 (January 19, 2019): 10–16. Accessed October 5, 2026. https://journals.bsu.by/index.php/mathematics/article/view/779.