SKORDEV, D. A reducibility in the theory of iterative combinatory spaces. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 98, p. 87–99, 2008. Disponível em: https://admin.uni-sofia.bg/index.php/fmi/article/view/131. Acesso em: 24 jan. 2025.