%0 Journal Article
%A Luis Montejano
%T About a problem of Ulam concerning flat sections of manifolds.
%J Commentarii mathematici Helvetici
%D 1990
%P 462-473
%V 65
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMH_1990__65_3_140207/
%F CMH_1990__65_3_140207