%0 Journal Article
%A Bruckner, A. M.
%A Laczkovich, M.
%A Petruska, G.
%A Thomson, B. S.
%T Porosity and Approximate Derivatives
%J Canadian journal of mathematics
%D 1986
%P 1149-1180
%V 38
%N 5
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1986-058-7/
%R 10.4153/CJM-1986-058-7
%F 10_4153_CJM_1986_058_7