%0 Journal Article
%A P.L. Butzer
%A W. Dickmeis
%T On the Sharpness of Non-Optimal Approximation for Semigroup Operators.
%J Manuscripta mathematica
%D 1985
%P 243-252
%V 51
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MM2_1985__51_155073/
%F MM2_1985__51_155073