%0 Journal Article
%A S. CARTER
%A S.A. ROBERTSON
%T Relations Between a Manifold and its Focal Set.
%J Inventiones mathematicae
%D 1967
%P 300-307
%V 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM_1967__3_141877/
%F IM_1967__3_141877