%0 Journal Article
%A D. B. Zot'ev
%T Contact degeneracies of closed  2-forms
%J Sbornik. Mathematics
%D 2007
%P 491-520
%V 198
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_2007_198_4_a2/
%G en
%F SM_2007_198_4_a2