%0 Journal Article %A Zofia Adamowicz %T A recursion-theoretic characterization of instances of $ΒΣ_n$ provable in $П_{n+1}(N)$ %J Fundamenta Mathematicae %D 1988 %P 231-236 %V 129 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-129-3-231-236/ %R 10.4064/fm-129-3-231-236 %G en %F 10_4064_fm_129_3_231_236