%0 Journal Article %A Carl Jockusch %T Recursiveness of initial segments of Kleene's O %J Fundamenta Mathematicae %D 1975 %P 161-167 %V 87 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-87-2-161-167/ %R 10.4064/fm-87-2-161-167 %G en %F 10_4064_fm_87_2_161_167