%0 Journal Article
%A V. N. Ushakov
%A A. A. Ershov
%A M. V. Pershakov
%T On one addition to evaluation by L.\,S.~Pontryagin of the geometric difference of sets in a plane
%J Izvestiya Instituta Matematiki i Informatiki Udmurtskogo Gosudarstvennogo Universiteta
%D 2019
%P 63-73
%V 54
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IIMI_2019_54_a5/
%G ru
%F IIMI_2019_54_a5