%0 Journal Article
%A V. S. Retakh
%T Homotopic properties of categories of extensions
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1986
%P 217-218
%V 41
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/RM_1986_41_6_a16/
%G en
%F RM_1986_41_6_a16