VELESNITSKII, V. F.; SEMENCHUK, V. N. On one Shemetkov problem. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 64, n. 9, p. 1282–1288, 2012. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2658. Acesso em: 5 dec. 2025.