%0 Journal Article
%A John R. Stallings
%T A topological proof of Grushko's theorem on free products.
%J Mathematische Zeitschrift
%D 1965
%P 1-8
%V 90
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZ_1965__90_170458/
%F MZ_1965__90_170458