Definability issues in the ω-Turing degrees. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 105, p. 45–54, 2018. DOI: 10.60063/gsu.fmi.105.45-54. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/11. Acesso em: 14 dec. 2025.