%0 Journal Article
%A P.L. Butzer
%A H.G. TILLMANN
%T Approximation Theorems for Semi-Groups of Bounded Linear Transformations.
%J Mathematische Annalen
%D 1960
%P 256-262
%V 140
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MAN_1960__140_160778/
%F MAN_1960__140_160778