Dimitrov, Rumen. “Characterization of the Effective Computability in $\mathfrak{f}$-Enumerations”. Ann. Sofia Univ. Fac. Math. and Inf. 87 (December 12, 1995): 61–72. Accessed January 15, 2025. https://admin.uni-sofia.bg/index.php/fmi/article/view/405.