HOLÁ, L'ubica; KWIECIŃSKA, Grażyna. On the Borel classes of set-valued maps of two variables. Annales Mathematicae Silesianae, [S. l.], v. 34, n. 1, p. 81–95, 2020. Disponível em: https://journals.us.edu.pl/index.php/AMSIL/article/view/13634. Acesso em: 12 apr. 2025.