%0 Journal Article
%A V. L. Selivanov
%T Index sets of classes of hyperhypersimple sets
%J Algebra i logika
%D 1990
%P 220-240
%V 29
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AL_1990_29_2_a7/
%G ru
%F AL_1990_29_2_a7