%0 Journal Article
%A V. I. Amstislavskii
%T Extension of recursive hierarchies, and $R$-operations
%J Doklady Akademii Nauk
%D 1968
%P 1023-1026
%V 180
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1968_180_5_a0/
%G ru
%F DAN_1968_180_5_a0