%0 Journal Article
%A Breves Filho, J.A.
%T On the normal systems of differential equations
%J Portugaliae mathematica
%D 1974
%P 199-201
%V 33
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/PORMA_1974__33_4_115239/
%G en
%F PORMA_1974__33_4_115239