%0 Journal Article %A Henk Barendregt %A Giuseppe Longo %T Recursion theoretic operators and morphisms on numbered sets %J Fundamenta Mathematicae %D 1983 %P 49-62 %V 119 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-119-1-49-62/ %R 10.4064/fm-119-1-49-62 %G en %F 10_4064_fm_119_1_49_62