1.
Dovghey Z, Sumaryuk M. Free subsemigroups in automorphism group of a polynomial ring of two variables over number fields. Carpathian Math. Publ. [Internet]. 2011 Dec. 29 [cited 2024 Apr. 25];3(2):64–70. Available from: https://journals.pnu.edu.ua/index.php/cmp/article/view/3066