%0 Journal Article
%A I. M. Krichever
%T Obstructions to the existence of $S^1$-actions. Bordism of ramified coverings
%J Izvestiya. Mathematics 
%D 1976
%P 783-797
%V 10
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM2_1976_10_4_a6/
%G en
%F IM2_1976_10_4_a6