BULINSKI, K.; OSTAFE, A.; SHPARLINSKI, I. . . Counting embeddings of free groups into $\mathrm{SL}_2(\mathbb{Z})$ and its subgroups. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, [S. l.], v. 26, n. 4, p. 2351-2362, 2025. DOI: 10.2422/2036-2145.202307_011. Disponível em: https://journals.sns.it/index.php/annaliscienze/article/view/6279. Acesso em: 20 feb. 2026.