%0 Journal Article
%A Iwona Krzyżanowska
%T Cross-cap singularities counted with sign
%J Algebra and discrete mathematics
%D 2018
%P 257-268
%V 25
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ADM_2018_25_2_a5/
%G en
%F ADM_2018_25_2_a5