%0 Journal Article
%A O. Widlund
%T On Best Error Bounds for Approximation by Piecewise Polynomial Functions.
%J Numerische Mathematik
%D 1976
%P 327-338
%V 27
%I mathdoc
%U http://geodesic.mathdoc.fr/item/NUMA_1976__27_132456/
%F NUMA_1976__27_132456